Services Hot Water Provisions for Commercial Buildings

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SERVICES HOT WATER (SHW)PROVISIONS RESEARCH PAPER for

COMMERCIAL BUILDINGS

For

Austral ian Building Codes Board

July 2003Revision 4

Project 16020


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TABLE OF CONTENTS

REPORT ISSUE AUTHORI SATION................................................ERROR! BOOKMARK NOT DEFINED.

EXECUTIVE SUMMARY ...................................................................................................................................3

1 INTRODUCTION .......................................................................................................................................41.1 BACKGROUND.......................................................................................................................................41.2 OBJECTIVES ..........................................................................................................................................41.3 EXCLUSIONS .........................................................................................................................................4

2 SERVICES HOT WATER..........................................................................................................................5

2.1 INTRODUCTION .....................................................................................................................................52.2 HEATTRANSFER EQUIPMENT................................................................................................................52.3 HEATINGENERGY SOURCE ...................................................................................................................6

2.3.1 Low cost waste heat.........................................................................................................................62.3.2 Non renewable direct fuels..............................................................................................................62.3.3 Mains electricity..............................................................................................................................62.3.4 Mains electricity Heat Pumps.......................................................................................................7

2.3.5 Solar ................................................................................................................................................7PIPING........................................................................................................................................................72.4 DISTRIBUTION SYSTEMS .......................................................................................................................72.5 OUTLET DEVICES /TERMINAL UNITS.....................................................................................................8

3 SHW DESCRIPTIONS FOR AL TERNATIVE BUILDING FORMS AND BUILDING CLASS.......9

3.1 INTRODUCTION .....................................................................................................................................93.2 BCACLASS2-APARTMENTS...............................................................................................................9

3.2.1 FormA and FormB.........................................................................................................................93.2.2 FormE.............................................................................................................................................9

3.3 BCACLASS3-HOTELS........................................................................................................................93.3.1 FormA.............................................................................................................................................93.3.2 FormD ............................................................................................................................................93.3.3 FormE.............................................................................................................................................9

3.4 BCACLASS5-OFFICES .....................................................................................................................103.4.1 FormA, FormB and FormD........................................................................................................103.4.2 FormE...........................................................................................................................................10

3.5 BCACLASS6RETAIL CENTRES /SALESOUTLETS ..........................................................................103.5.1 FormB and FormC ......................................................................................................................103.5.2 FormD ..........................................................................................................................................10

3.6 BCACLASS8-LABORATORIES..........................................................................................................103.6.1 FormC and FormD......................................................................................................................10

3.7 BCACLASS9HEALTH CARE AND EDUCATIONAL BUILDINGS.........................................................103.7.1 FormB and FormC ......................................................................................................................103.7.2 FormD ..........................................................................................................................................10

4 DESIGN OPTIONS FOR SIZING SERVICES HOT WATER ............................................................11

4.1

INTRODUCTION ...................................................................................................................................114.2 BUILDINGFUNCTION...........................................................................................................................11

4.3 HEATTRANSFER EQUIPMENT..............................................................................................................124.3.1 Instantaneous systems selection considerations............................................................................124.3.2 Storage systems selection considerations......................................................................................134.3.3 Storage systems configuration.......................................................................................................144.3.4 Storage systems scheduling...........................................................................................................14

4.4 HEATINGENERGY SOURCE .................................................................................................................154.5 DISTRIBUTION SYSTEMS .....................................................................................................................15

4.5.1 Piping............................................................................................................................................154.5.2 Pipe insulation...............................................................................................................................164.5.3 Pumps............................................................................................................................................19

4.6 OUTLET DEVICES / TERMINAL UNITS...................................................................................................214.7 WARM WATER SYSTEMS ....................................................................................................................22

16020 Revision 4 page 1 of 50


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5 SERVI CES HOT WATER USAGE PROFILES....................................................................................23

5.1 INTRODUCTION ...................................................................................................................................235.2 PREDICTED SHWUSAGE PROFILES .....................................................................................................23

6 SHW ENERGY SAVING OPTIONS AND ENERGY CONSUMPTION GUIDELINES..................24

6.1 ENERGY SAVINGOPTIONS ..................................................................................................................24

6.1.1 Heat Transfer Equipment..............................................................................................................246.1.2 Heating Energy Source..................................................................................................................256.1.3 Distribution Systems......................................................................................................................256.1.4 Outlet devices / Terminal units......................................................................................................26

6.2 ENERGY CONSUMPTION GUIDELINES..................................................................................................26

7 AVERAGE SEASONAL COL D WATER SUPPL Y TEMPERATURES............................................30

8 RECOMMENDED BCA AND AUSTRAL IAN STANDARD AMENDMENTS.................................32

APPENDIX A BUI LDING FORMS................................................................................................................35

APPENDIX B STANDARD SHW SYSTEM DEFINITI ONS AND FEATURES.......................................37

APPENDIX C APPL ICATION SIZING GUIDES.........................................................................................40

APPENDIX D SERVI CES HOT WATER SIZING GUIDE.........................................................................42

APPENDIX E USAGE PROFILES.................................................................................................................43

APPENDIX F REFERENCES........................................................................................................................50

This report is based specifically on confidential briefing information provided by the Client and is not intended foruse by unauthorised persons or parties. No warranties are made to any unauthorised persons or parties in

respect of the contents of this report.

SEMF Holdings Pty. Ltd45 Murray StreetHobart TAS 7000

A.C.N. 009 543 702

Telephone (03) 62311211Facsimile (03) 62348709

Email [email protected]



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EXECUTIVE SUMMARY

This report describes the outcomes of an investigation of Services Hot Water (SHW)efficiency measures suitable for inclusion in the BCA proposed energy provisions forcommercial buildings, Class 2 to Class 9B.

The report outlines typical SHW systems for a range of different building forms andclassification types and the various features associated with these systems. Typical usageprofiles, energy consumption guidelines and SHW sizing concepts are detailed.

A range of potential energy saving measures is identified for the various components in SHWsystems.

Whilst no specific recommendations are required in relation to this report, we wouldrecommend that a MEPS program and performance criteria for boiling water units (BWU) beimplemented as it was identified during our investigation that no regulatory controls for BWUscurrently exist and these units use a considerable amount of energy.

Simplified guides to assist in the design of SHW systems and in the calculation of SHWenergy consumption are also provided within this report.

A range of potential minimum requirements for implementation into the BCA are identified,including the possible development of an Australian standard for boiling water systems and apackage of best practice design notes.



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1 INTRODUCTION

1.1 Background

The Australian Building Codes Board (ABCB), in cooperation with the Australian Greenhouse

Office (AGO), is developing energy efficiency measures suitable for inclusion in the BuildingCode of Australia (BCA). A number of technical working groups have been established toassist the ABCB in developing suitable cost effective technical energy efficiency measuresfor inclusion in the BCA.

Commercial Working Group Number 4 (WGC4) is specifically looking at the HVAC andService Hot Water (SHW) services.

As a preliminary to WGC4s consideration of SHW energy measures, identification of thestandard design concepts for SHW systems was required. Hence, the ABCB Office soughtexpert advice on SHW systems that met the objectives described below.

1.2 Objectives

The specific objectives of the SHW review are as follows:

1. To identify typical SHW for a range of representative buildings and variations for thevarious classes of building;

2. To provide specific descriptive advice on these systems including control features,maximum pipe work lengths, recirculating pumps, scheduling of multiple heating unitsand heating unit configurations;

3. Identify how SHW systems are sized;

4. Identify energy saving features in SHW systems, indicative costs and energy efficiencysavings that such features could realise;

5. To provide recommendations on how to estimate energy consumption, including unitstanding losses, piping losses and water heating based upon average supply watertemperatures and activity profiles;

6. To identify average seasonal supply water temperatures for state and territory capitalcities and Cairns, Coffs Harbour, Geraldton, Alice Springs and Kalgoorlie; and

7. Provide standard usage profiles for each of the building forms and classes.

1.3 Exclusions

This review is intended to only investigate SHW systems for provision of potable water totenants and occupants within buildings. It is not intended to be a review of Swimming pools,Spas or the provision of hydronic space heating systems.

The specific sizing of SHW systems is not included within this commission, however generaldesign and sizing guidelines are outlined within this report.

Details on Services Hot Water for process applications is also excluded.



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2 SERVICES HOT WATER

2.1 Introduction

For the purposes of this report we have defined Services Hot Water systems only in the

context of the delivery of potable water to occupants. SHW system design is controlled by anumber of regulatory systems including AS3500.1.2:1998 Water supply - Acceptablesolutions, AS3500.4.2:1997 Hot water supply Acceptable Solutions, NSW Hosplan Codeof Practice on thermostatic mixing valves (TMVs) and various local authority requirements ineach State and Territory.

SHW systems may consist of distributed instantaneous heating and storage water systemsand local boiling water units. SHW systems consist of four primary components, viz., theheat transfer equipment, the heating energy source, the piping distribution system, and theoutlet devices or terminal units.

2.2 Heat Transfer EquipmentTwo primary forms of heat exchange units are used in Services Hot Water systems to raisethe cold-water make-up water to the required supply water temperature. The primary heattransfer systems typically consist of storage water units with some form of immersion heateror heat exchange mechanism. The second form of heat transfer consists of instantaneousheating, which adds heat directly to the distributed water. Note that some of the newer SHWsystems on the market consist of a combination storage and instantaneous heating.

For commercial buildings, heating is primarily provided by either gas or electricity althoughheat reclaim and solar collectors are also used.

Gas heaters are capable of being labelled in Australia, with an energy star-rating scheme,

similar to that utilised for electrical equipment. Gas equipment is rated under an AustralianGas Association scheme (AGA), using their Method of Test for Energy Labelling of SpaceHeaters AG103 MOT 5.18.1 1998. Details on the energy rating of gas-fuelled systemscan be reviewed on the web site www.gas.asn.au

Electric Storage heaters are labelled under a similar Minimum Energy Performance Scheme(MEPS). Electric Storage water heaters are labelled using AS1056.1 1991 under theenergy rating scheme managed by the Australian Greenhouse Office. Details on theenergy rating of electric storage hot water cylinders can be reviewed on the web sitewww.energyrating.gov.au. Under this scheme electric storage heaters must meet theminimum efficiency requirements of the standard to be allowed to be sold within Australia.The efficiency requirements are based on standing heat losses of the storage vessels. Astar rating system, similar to that used for gas water heaters to compare the relative

efficiency of models, has not been setup for electric hot water heaters.

It is evident that there are some shortfalls in current regulatory requirements in terms of heattransfer equipment. Whilst the design and efficiency requirements of storage hot watersystems are stipulated by Australian Standards, there are no similar regulations for theefficiency or construction of Boiling Water Units. Given the number of BWUs installed incommercial buildings, we believe that a MEPS rating scheme needs to be instigated.

Note in some instances it may be a requirement to consider duty and standby systems,particularly in centralised designs to ensure that the end users are not disadvantaged shouldthe centralised option generate a fault.

http://www.gas.asn.au/http://www.energyrating.gov.au/http://www.energyrating.gov.au/http://www.gas.asn.au/


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2.3 Heating Energy Source

A number of alternative energy sources exist for SHW systems. These may be electrical(either direct electric or heat pump), solar (either Photovoltaic or solar collector), fuel(typically LPG or Natural Gas) or recovered waste heat (i.e. flue gases, refrigeration cycles,process water, etc.)

Heating energy sources can be categorised into the following types.

2.3.1 Low cost waste heat

A source of waste heat may already exist as part of the buildings process systems. This maybe fluids which have been utilised as cooling agents for process systems. Examples includeheat rejected from refrigeration for cool rooms and freezer plant and heat from wastewater.Alternatively a cogeneration plant, which typically consists of a fuel driven engine generatingelectricity for a building, can provide waste heat from the engines exhaust and cooling jacketby passing the waste heat through heat exchangers for distribution to the domestic hot water.

The heat exchangers need to be constructed to meet the requirements for potable water.These are commonly engineered on a project-by-project basis, however the ROTEX system

distributed by Origin Energy is a standardised mass produced heat exchanger specificallydesigned for this application.

2.3.2 Non renewable direct fuels

Natural Gas and LPG are the two most common fuels for use with SHW systems. Naturalgas has a number of advantages over LPG in that it generates fewer greenhouse gases thanLPG and is also significantly cheaper as a fuel source. Gas fired SHW systems can operateacross a broad range of efficiencies, with ASHRAE 90.1-1999 specifying minimumefficiencies of 62% for heating units below 58kW and ranging between 75% and 80% forlarger units. When considering gas heated units exact details need to be sought from themanufactures heating transfer equipment data sheets.

2.3.3 Mains electricity

Standard mains electricity systems are available in two options:

Standard tariff electric ity

Standard tariff electricity is the most common SHW heating energy source.Electricity has a number of disadvantages in that it generates the highestgreenhouse gases of all fuel sources (with the exception of green power schemes)and is the most expensive fuel type with the exception of LPG. The advantages ofelectricity are that it is the only convenient fuel source for boiling water units and that

standard hot water cylinders are at their most economical capital cost whenoperating on mains electricity. In addition it is a very easy energy source to supplyto SHW heating systems.

Off peak electric ity

Off peak electricity offers an advantage over standard tariffs in that electricity isprovided at a cheaper tariff than at the standard tariff. However, off peak electricityis only available at specific times for limited periods. To use an off peak tariff SHWsystems require correctly sized storage tanks that can accommodate the standinglosses and the SHW draw-off during the day.



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It should be noted that greenhouse gas emissions are significant if a non-renewableelectricity source is used.

2.3.4 Mains electricity Heat Pumps

Standard mains electricity is utilised in heat pump water heaters that use a standard vapourcompression refrigeration cycle to extract heat from ambient air and reject heat into thestored water to heat the water to the required temperature. By drawing the heat from theatmosphere, heat pumps have efficiency in the region of 300% over standard electricalstorage water systems and offer significant energy saving benefits.

Heat pumps operate on a similar principle to refrigerators where heat is transferred from oneplace to another. This is achieved by cold liquid refrigerant collecting heat from ambient airand changing from a liquid to a gaseous state, the compressor compressing the refrigerantgas to a high pressure, thus raising its temperature, and subsequently rejecting heat from thehigh pressure, high temperature gas to the water storage tank. This heat transfer liquefiesthe refrigerant in the process.

There are two main types of heat pump systems. The first works as a standard air sourceunit, which is integral to the storage tank, with a fan to force air over an evaporator to soakup the ambient heat and a coil in the storage tank through which heat is rejected to thewater. The second type is a solar boosted heat pump, in which the air warmed evaporator isreplaced by a solar panel exposed to solar radiation. In this unit the refrigerant is pipedthrough the panel and is heated up by both solar radiation and ambient air. The heatrejected from the refrigeration cycle is again discharged via a coil in the storage tank to thewater.

Domestic style heat pump systems have very few limitations, with heat pumps being suitablefor operation in most weather conditions. Some systems are claimed to operate correctly attemperatures below 0oC. The common style of heat pump is capable of maintaining a watertemperature of approximately a maximum of 60oC without any boost heating system.However in SHW systems for kitchen applications, require water at approximately 80oC, an

in-line booster is necessary.

Heat pump systems are generally only available up to approximately 350L capacity.

2.3.5 Solar

This is the most greenhouse gas friendly energy source. Some form of booster is stillrequired, particularly in colder climates, to assist in times of low solar availability. Boostersystems are typically electricity, gas or LPG. Two primary forms of solar-fuelled hot watercylinders are available from the standard solar collector, which circulates the water through asolar collector panel and thereby picks up heat from the available solar gains, to photovoltaictechnology. The PV cell option is the more expensive of the two.

2.4 Piping Distribution Systems

This is the piping network which allows the hot water to be distributed to any requiredlocation in a building. It may include circulation pumps. A cold-water make-up is provided toreplenish water drawn from the SHW system

In Australia, the distribution piping is commonly constructed from copper piping and copperbased fittings. However, the prevalence of blue water problems in copper piping systems isresulting in the use of cross linked polyethylene or similar approved plastic pipe as analternative piping material. Consideration of local environmental conditions, in terms of thewater quality, should be considered in respect of determining pipe materials.



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2.5 Outlet devices / Terminal units

These are the plumbing fixtures through which hot water is delivered to the user. They mayinclude mixing devices to control water delivery temperatures or deliver water at the sametemperature as the distributed water system.

As Legionella can occur in water systems, outlet devices need to be selected to minimise

potential health problems if the water temperature is dropped below 50 oC. This appliesspecifically to thermostatic mixing valves and the like.

A significant array of outlet devices exist, the evaluation of which is beyond the scope of thisreview, however details of typical outlets, that are used in the majority of installations, andtheir flow rates are identified in Appendix D. Where specialist equipment is connected to theSHW system, designers can obtain flow rates, temperature ranges and any other relevantdesign details from the manufacturers literature.

The usage patterns of outlets vary significantly depending upon the buildings usage profileand its functional requirements.



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3 SHW DESCRIPTIONS FOR ALTERNATIVE BUILDING FORMSAND BUILDING CLASS

3.1 Introduction

As part of the ABCB proposed implementation of energy efficiency measures in the BCA, aset of representative building forms has been developed to standardise the energy efficiencyrequirements between all of the various investigative and technical committees.

A total of five standard building forms have been developed described as Forms A, B, C, Dand E. Each building form could potentially be utilised as a different Class of building asdefined by the BCA one of Class 2, 3, 5, 6, 7, 8 or 9. Definitions for the various buildingforms and building class can be found in Appendix A.

Appendix B provides, in the form of a table, the definition of the standard SHW systems,which would be provided for the various building forms and classes.

Definitions for the SHW systems, which would typically be provided for the various building

forms and building Class, are described in the following sections.

3.2 BCA Class 2 - Apartments

3.2.1 Form A and Form B

It is recommended that a localised SHW system be provided for each apartment. Systemscan be either storage or instantaneous. An alternative is a centralised storage SHW systemsupplying hot water to several floors. The SHW water flow to each apartment can bemeasured to allocate energy costs.

3.2.2 Form E

Localised SHW systems for each apartment. Systems can be either storage orinstantaneous.

3.3 BCA Class 3 - Hotels

3.3.1 Form A

A central storage SHW supplying SHW to several floors is recommended. A singlerecirculating system would usually be provided to supply a number of floors, typically 3 to 4floors for a Form A building and all three floors of the Form B building.

3.3.2 Form D

A central storage SHW supplying all SHW points on the floor is recommended. Therecirculating system would be designed and installed to accommodate the SHW needs of thewhole building.

3.3.3 Form E

Localised SHW systems for each apartment. Systems can be either storage orinstantaneous.



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3.4 BCA Class 5 - Offices

3.4.1 Form A, Form B and Form D

Depending on the size of the tenancy, a localised storage system is recommended for eachoffice. In the case of small tenancies it may be appropriate to install a centralised systemthat supplies SHW to each tenancy. The common amenities areas would be supplied from acentralised SHW system.

3.4.2 Form E

Due to small size of the building it is recommended that localised storage SHW systems beprovided for each office. The SHW systems for the office areas may also supply the buildingamenities area.

3.5 BCA Class 6 Retail Centres / Sales Outlets

3.5.1 Form B and Form C

Localised storage or instantaneous systems for each tenancy. The common amenities areaswill be supplied with a centralised recirculating SHW system.

3.5.2 Form D

Localised storage or instantaneous systems for the tenancy. The amenities areas could beprovided from the tenancy systems or by a separate localised storage or instantaneoussystem.

3.6 BCA Class 8 - Laboratories

3.6.1 Form C and Form D

Instantaneous systems are recommended as most laboratory environments typically uselarge volumes of cold water and low volumes of hot water on a variable as required basis.

Amenities areas could be supplied from the laboratory SHW system or from a localisedstorage or instantaneous system.

3.7 BCA Class 9 Health Care and Educational Bui ldings

3.7.1 Form B and Form C

Typically, the common amenities areas would be supplied from a centralised recirculatingSHW system. Localised storage systems or instantaneous systems would be provided forspecial purpose spaces or isolated areas.

3.7.2 Form D

A reticulated central storage SHW throughout the floor is recommended. The amenitiesareas would be supplied from this system.



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4 DESIGN OPTIONS FOR SIZING SERVICES HOT WATER

4.1 Introduction

A wide range of technical literature is available for the design and sizing of SHW systems.

The technical resources which were reviewed as part of this investigation, and upon whichthe following design information is based, included:

ASHRAE/IES Standard 90.1-1989 Users Manual, November 1992 ASHRAE;

1999 ASHRAE Applications Handbook SI 1999 ASHRAE;

RHEEM Hot Water Manual 2000 Rheem Australia;

DUX Hot Water Catalogue 1999 Dux Australia;

AIRAH Handbook Millennium 3rd edition, January 2000 AIRAH; and

Rinnai Hot Water Manual 2000 edition, Rinnai Australia.

In addition to these design guides the designer must incorporate, when required by approvalauthorities, the relevant sections of AS/NZS 3500 National Plumbing and Drainage Code.

In designing the SHW system the design process needs to be broken up into the various keycomponents of SHW systems as defined in Section 2.

The designing of SHW systems incorporates the following steps:

1. Building function and size to determine usage patterns;

2. Identification of all areas in which hot water will be utilised, including type and form ofoutlet devices and water flow rates;

3. Identify peak demand periods;

4. Identify supply water temperature requirements;

5. Determine most suitable energy option, including a life cycle review of alternatives;

6. Select appropriate heat transfer equipment option;

7. Identify available storage spaces for location of heat transfer equipment; and

8. Design of distribution system, including pipe sizing, insulation and pumpingrequirements.

9. Selection of outlets including flow restriction devices if appropriate

4.2 Building Function

The BCA provides within Part F2 of Volume 1 a calculation for the number of occupants andminimum required fixtures for buildings. Note that the requirements of the BCA in this areaare prescriptive requirements and where the number of occupants is known, this value maytake precedence over the BCA Table D1.13.

A determination of the function of the space, in relation to the BCA building classification,allows the designer to allocate peak flow rates and hot water usage patterns in the selectionof the most appropriate SHW system.



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Appendices C and D provide recommendations for typical hot water usage patterns forvarious building classifications, including design flows and peak usage periods.

4.3 Heat Transfer Equipment

The most popular choices for provision of hot water to a variety of applications are either bystorage units or instantaneous units. Both systems can be installed as either a single unit orin a multiple configuration dependent upon user requirements.

Both of the systems described are suitable for single domestic type applications or byextending to multiple manifolded units are suitable for larger applications.

The storage design option relies on an energy source to heat water within a storage vesselsized to provide sufficient hot water for a pre-determined level of use. The level of use iscalculated from expected usage rates of hot water for a fixture (i.e. basin, shower etc). Theusage rates for all of the fixtures on the SHW system are summed and then allowance madefor diversity of use to give the maximum hot water volume to be held in storage. The storagevessel is fitted with heating elements that have the capacity to heat the stored water, some of

which has been drawn off by the various fixtures, within a particular time period (recover theheated level of the stored water at pre-determined rate). For particular size storage units therecovery rate is governed by the size and number of heating elements, if electricity is theheating element, or the capacity of an attached gas fired instantaneous heating device, if gasis the chosen heating medium. Storage units are manufactured in a large variety of sizesand capacities and are usually housed in metal cabinets, which are either cylindrical orrectangular in external shape.

Within NSW the Australian Gas Limited Company (AGL) has a number of requirements forthe design of SHW systems involving gas heaters which requires a minimum 80% efficiency.The efficiency is based on the heat losses of the flow and return pipe work and the heattransfer equipment as a combined system.

The more recently developed gas instantaneous units are generally small in volume, can beelectronically programmed to differing temperatures and deliver limitless (subject tocontinuity of fuel source) hot water.

The selection of solar or heat pump systems should be considered as one of the moreenergy efficient systems.

The Rheem hot water book provides a table of advantages and disadvantages associatedwith the most common forms of heating water and is a recommended resource for SHWdesigners.

4.3.1 Instantaneous systems selection considerations

Determine available space and identify any restrictions. Typically, the fuel source is gas butelectric systems are also available.

Location typically external, if internal then a ventilation system may be required.

Internal Flue Cost and practicality of fluing options, less practical generally if not on anexternal wall, particularly in a multi storey application.

Visual Impact A flue grille may not be permitted to exit on a heritage rated building orbuilding element or onto a pedestrian way. The flue grille should be unobtrusive, clear ofoutside air intakes and windows and comply with the relevant gas code, and vulnerability tovandalism in non secured area can be an issue.



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External Flue Points to note are that the local atmosphere could be corrosive, the visualimpact of the flue, what local planning rules require, are there any heritage issues, provisionof access to gas source, provision of access for maintenance, and the need for securitycovers.

Control Systems: The instantaneous unit can be remotely controlled by the user oralternatively pre-set to deliver water to fixtures. The units can also be pre-programmed todeliver water at lower temperatures for warm water systems although these must incorporatesome facility for regular disinfection of the entire system. Many instantaneous systems aresupplied with microprocessor controllers, which can program the scheduling of multiple units.These systems can also be managed by building a building management and controlssystem (BMCS).

Advantages: - Limitless supply of hot water utilising a variety of selection methods fortemperature control. Energy savings achieved by not needing to store large volumes of preheated water for intermittent use.

Disadvantages: - External space requirements for gas storage if LPG is the energy source.

The units should allow for controlled short-term temperature rises for disinfection or

alternatively the delivery system to which they are attached can be fitted with an ultra-violetdisinfection lamp.

4.3.2 Storage systems selection considerations

Space the space required for the installation and maintenance.

Location external location as opposed to internal, the visual impact, sometimes necessaryto locate units at a distance from fixtures due to space limitations. Generally should belocated as close as possible to fixtures that require a short / quick supply of hot water.

Internal - Space availability, impact on other building elements for replacement, potential fordamage to adjacent building elements resulting from failure of the water storage tank(s),disruption to building function for replacement. Seek advice from the water authority on theirhistorical knowledge of tank failures so that the storage tank selected provides a lifeappropriate to the system. Determine water pH in the area as it can have an adverse effecton storage tank life.

External Assess the visual impact, the vulnerability to vandalism in non-secured areas, ifcorrosive atmosphere is a problem, and if electric, what is the access to the power source.

Control Systems: The storage units are typically on-off control from a thermostat mountedwithin the storage vessel to control stored water temperature. For load scheduling purposesit may be possible to accept lower hot water temperatures when heating elements are

initiated by a BMCS to limit maximum demand.

Advantages A storage system will provide a reservoir of hot water for a limited time in theevent of an energy failure. They provide simplicity of installation with few moving parts.

Disadvantages - A prolonged initial heat up period is required. The storage tanks occupy alarge amount of space. If the amount of water storage is limited then the reheat time can belonger. There is potential to cause significant property damage in the event of a failure of thetank.



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4.3.3 Storage systems configuration

Configuration of units is required to address the diversity of applications for hot water unitinstallation. Items for consideration are:

Type and style of facility;

Known ambient water temperature;

Required temperature rise;

Known capacity of selected unit(s) to meet criteria;

If a storage system with remote heating, location of the storage unit; and

Cross reference to unit type selection.

The various areas within a facility may have varying hot water temperature requirements,ranging from 82oC in a restaurant kitchen to approximately 42oC in nursing homes.Consideration should be given to selection of separate heating water systems for specificareas, such as kitchens, to avoid heating water to the maximum temperature and thencooling down again to supply the remaining areas that typically may only require 60oC water.

Storage system configurations may vary from individual systems located adjacent to theoutlets to large central systems located in a common area with a flow and return distributionnetwork. Each system has its own advantages and disadvantages.

Where the hot water storage system is remote from the heating source, eg., heat reclaim,wood fired, or some solar collector systems, the storage tank should be insulated to so that itprovides a heat loss no greater than that of an integral heat source/water storage unit.

4.3.4 Storage systems scheduling

The units, regardless of type and style, can be installed in multiples to address the specificneeds of the facility being served. Storage units can be installed in parallel with the hot watersupply being drawn equally from all storage units to meet demand or alternatively throughthe installation of electronically controlled valving and switching can be drawn on a unit-by-unit basis.

A criterion for this component of design is identified as follows:

Type and style of facility;

Known ambient water temperature;

Known rate of use, in litres per second, to meet the demand of fixtures; and

Minimum level of either storage or achievable delivery rates.

Where there are a number of storage units are installed to meet the SHW demands thesystem should be provided with an expansion system such that water is not lost from thesystem. This expansion system needs to comply with the requirements of providing potablewater.



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4.4 Heating Energy Source

The selection of the heating energy source is dependent upon a number of factors includingavailable equipment types that can meet the functional requirements of the SHW system,and their proposed location.

The unit cost of energy, and its impact on the life cycle costing, generally determines the

energy source and the heating system efficiency. A life cycle analysis is recommended, asthe more economical energy sources are often associated with the highest capital-intensiveheating transfer equipment.

Consideration of the greenhouse gas generating levels of energy sources is becoming acritical issue with preference being towards energy sources that have very low emissionlevels.

The following points need to be considered in the selection of SHW systems:

Cost of energy source.

User preferences.

Availability of the energy source, i.e., whether gas main piping is available nearby forconnection, the availability of mains electricity, the extent of any solar contribution, ifthe electrical infrastructure is adequate. Limitations in the electrical infrastructurecould mean that gas or some other form of energy source are the only availableoptions unless significant expenditure is made to upgrade the electrical supplies.

With electrical systems there are a number of different tariff systems which can havean impact upon the selection of the heat transfer equipment. The main tariffsavailable include:

Continuous, 24 hour supply;

Off peak, where energy is only available at specific times; and

Maximum demand which applies a charge for each kW of energyusage at a particular instance in time, but offers a cheaper unitelectricity rate.

4.5 Distribution Systems

The distribution system comprises the water piping, the piping insulation and, if necessary,circulating pumps.

4.5.1 Piping

The determination of pipe systems and piping working lengths is governed by the following:

Code stipulations for maximum allowable linear run of smaller diameter pipe, i.e.AS/NZS3500.5: 2002 Domestic Installations;

Head loss;

Friction loss;

Demand of the fixtures and fittings to be connected to the subject pipe in terms of flowrates;

Piping materials; and



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Allowable temperature losses from the heat transfer equipment to the outlet device.

A number of pipe sizing guidebooks are available to enable sizing of the piping distributionsystem to meet the peak demand at an acceptable pressure loss. Whilst it is difficult toprovide guidelines for what is an acceptable pressure loss, the pressure losses should beminimised to ensure that minimum pressure levels are achieved at the outlet. Guidebooksinclude the AIRAH handbook, Application Manual DA19 and ASHRAE 1997 Fundamentals.

The designer should review the local water quality to determine if piping materials other thancopper need to be considered.

In large systems balancing of the piping network will need to be undertaken to ensuresuitable water delivery occurs when multiple outlets are drawing water. This is particularlyimportant where multiple risers / droppers exist or multiple horizontal circulating loops exist.

Check valves should be installed in the return lines.

Backflow prevention devices may need to be considered in specific instances. Reference tothe relevant Australian Standard AS/NZS3500.1.2

A common rule of thumb criterion, to assist in the sizing of hot water piping networks, is thathot water needs to be available at any terminal device, eg. a tap, within 30 seconds of theterminal device being opened.

A rule of thumb design for a typical flow velocity is around 1.8m/s.

Pipe insulation

The insulation of heating water pipe work is critical in SHW systems to overcome thepotentially high level of heat loss that radiates from uninsulated pipe work. Insulation of pipework has been proposed for regulation within Volume 2 of the BCA, through a recommendedamendment to AS/NZS3500.4.2 and similar provisions are recommended for Volume 1.

In NSW the AGL requires that all hot water piping be insulated with minimum 25mm thickinsulation.

The BCA requires that any insulation product not add to the fire potential of a building andtherefore must have a zero flammability index.

The minimum piping insulation requirements proposed in Energy Efficiency Measures BCAVolume 2 (Housing Provisions), Amendment No. 12 Prepublication Draft, November 2002.forSHW reticulation pipe work in domestic applications is climate zone based. This could alsobe utilised as the basis of SHW systems for Commercial building. The proposed measuresare shown in the following table.



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TABLE 4.5.2-1 Proposed BCA Housing Provisions for Insulation of SHW Piping

Minimum Thermal Insulation

Minimum Total R- ValuesSystem Location of Piping to be insulated

ClimateZone A

ClimateZone B

ClimateZone C

All hot water piping encased within a concrete floorslab

0.2 0.2 0.2Internal piping

All flow and return piping that is:

within an unventilated wall space, or

within an internal floor between storeys, or

between ceiling insulation and a ceiling

0.2 0.2 0.2

All flow and return piping 0.3 0.45 0.6

Cold water supply piping within 500mm of connectionto the central water heating system

0.3 0.45 0.6

Piping locatedwithin a ventilatedwall space, anenclosed buildingsub-floor or a roofspace Relief valve piping within 500mm of the connection to

the central heating water system0.3 0.45 0.6

All flow and return piping 0.3 0.6 0.6

Cold water supply piping within 500mm of connectionto the central water heating system

0.3 0.6 0.6

Piping locatedoutside thebuilding or in anenclosed building

sub-floor or a roofspace Relief valve piping within 500mm of the connection to

the central heating water system0.3 0.6 0.6

Notes:

1. Piping within a timber member, such as passing through a wall stud, is considered to have sufficientinsulation for the purposes of the above table.

2. Acceptable pipe insulation material, include but is not restricted to:a. 9mm of closed cell polymer, R = 0.2b. 13mm of closed cell polymer, R = 0.3c. 19mm of closed cell polymer, R = 0.45d. 25mm of closed cell polymer, R = 0.6

3. Climate Zones A, B and C include the following Capital Cities and reference towns:a. Zone A Coffs Harbour, Sydney, Alice Springs, Darwin, Brisbane, Cairns, Perth, Geraldton and

Adelaide;b. Zone B , Melbourne, Canberra, Hobart and Kalgoorlie andc. Zone C Alpine Areas

ASHRAE 90.1-1989 stipulates the minimum pipe insulation thickness requirements shown inthe following table.



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TABLE 4.5.2-2 ASHRAE 90.1 1989 Insulation Thicknesses for SHW Piping

Temperature Nominal Pipe diameter

Dead legs up to50mm dia

125mm and less 32mm to 50mm 65mm to 100mm 125mm and

above

>40oC 12.5 mm 25.0 mm 25.0 mm 38.0 mm 38.0 mm

Notes:

1. Dead legs to individual terminal outlets of a maximum length of 3660mm2. The above requirements relate to recirculating sections of SHW systems and the first 2.5m

from storage vessels of non-recirculating systems.

We note that the ASHRAE requirements are in many instances more stringent than the

proposed ABCB recommendations within Volume 2 of the BCA. For commercial applicationsthe ASHRAE recommendations would appear to be more suitable, but consideration ofenvironmental effects as proposed for AS/NZS3500 should be included. A combination ofthe more stringent recommendations in each document would result in the followingtabulated proposal for SHW insulation thicknesses.

TABLE 4.5.2-3

ClimateZone

Nominal Pipe diameter

Any sizeencased in

concrete floor

Dead legs upto 50mm dia

125mm and

less32mm to

50mm65mm to100mm

125mm andabove

A 12.5 mm 12.5 mm 25.0 mm 25.0 mm 38.0 mm 38.0 mm

B 12.5 mm 12.5 mm 25.0 mm 25.0 mm 38.0 mm 38.0 mm

C 12.5 mm 12.5 mm 25.0 mm 25.0 mm 38.0 mm 38.0 mm

The calculation of minimum insulation for pipe work is provided within ACI Insulation datasheets, and the formula to calculate this value is as follows:

r2loge(r2/r1) = k(td-top) / (fo(ta-td)

Where:r2 = pipe thickness + insulation thicknessr1 = pipe thicknessk = thermal conductivity of insulation W/mKtd = dew point temperaturetop = operating temperature of equipmentfo = surface coefficient of air filmta = surrounding ambient temperature

Whilst the above equation provides the calculated minimum insulation thickness it isrecommended that a 12mm thick safety margin be added to the calculated thickness.



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4.5.3 Pumps

Pumps are installed in SHW piping systems to ensure that hot water will be available at aterminal point at a adequate flow rate and pressure and within a reasonable period of time.

When selecting pumps the designer needs to consider whether primary or secondarypumping is appropriate for the piping system.

Primary Pumping:

Primary pumping is generally used to supplement the delivery of cold make-up water to theheating units (storage or instantaneous) where the cold water supply is inadequate. Theneed for primary pumping should be assessed on available delivery pressure, expected headand friction losses within the internal components of the system and the known demand ofthe fixtures to be served.

Secondary Pumping:

In secondary pumping the secondary (or circulating) pump is located beyond the heatingunits and circulates water in a delivery loop back into the heating or storage tank. If the

pump is adequately sized this ensures that the hot water in the loop is such that, when aterminal unit is opened, there is only a short delay before hot water is available at theterminal unit.

In hot water systems where the supply temperature is above 60oC circulation of hot water inthe loop contains the growth ofLegionella. At 60oC Legionella is killed over a 10-hour period.(Higher temperatures speed up the rate of kill but a higher SHW temperature is notnecessary for by maintaining a temperature at all times above this minimum temperature of60oC Legionella will not grow)

Individual fixtures or thermostatic mixing valves can be connected off the loop and thus areserved with a continuously upgraded supply of hot water.

Generally a circulating pump is selected based on the following criteria:

Static pressure available at the cold water main connection;

Length of service loop pipe;

Friction loss in the loop piping;

Pump head loss through the system;

Demand of the fixtures attached to the system in terms of minimum workingpressures and flow rates; and

Appropriate corrosion resistant materials.

Secondary Pump Sizing:

Typically, the secondary pump is sized as follows:

Determine an allowable temperature loss from the heat transfer equipment and thereturn water manifold. Typically a temperature drop of between 5oC and 10oC (t) isselected. This temperature differential is determined from the minimum storage watertemperature of typically 60oC and the lowest recommended supply temperature of50oC to avoid potential Legionella problems. The higher the temperature differentialthe lower the flow rate that is required and hence lower pumping energy use and heatloss from the distribution system. Consideration needs to be given to lengths of deadlegs as this may require a lower temperature differential in the flow/return line to



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ensure that water in dead legs is at a reasonable temperature to avoid potentialLegionella problems.

Calculation of heat loss in watts per hour from the flow and return pipe work (watts).

The above is used to determine the minimum return water flow rate as follows:

Flow rate, L/s = Heat loss (W) / (4.186 x 1000 x t)

From the return water flow rate, and knowing the total system resistance head, asuitable circulation pump can be selected from a manufacturers pump data literature.

The recommended minimum flow rate is 0.05 l/sec (3.0 l/min.) and the maximumrecommended flow rate in pipe work is 3.0 l/sec (180 l/min). These flow rates may beadjusted if instantaneous heater or storage water devices are used.

The level of sophistication of the system is determined by assessing the number of outlets tobe served and the conditions in which the system is to be installed. The system should bedesigned to achieve the best levels of efficiency in terms of water delivery and energyconsumption.

Circulating pumps should be provided with time clock control in instances where usage is notcontinuous, i.e. offices. To improve energy efficiency, pumps should be controlled by thefollowing mechanisms, particularly in larger installations:

Control via a thermostat in the return water line to operate the pump over anacceptable temperature range; and

Consideration could be given to installation of a pressure sensor in the piping networkfor control of pump speed via a VSD on the pump. This will provide energy savingswhere variable loads occur.

The following tables outline heat loss rates for bare and insulated piping systems. Thesetables can be used to estimate the heat loss from the piping and hence allow the pumpcirculation flow rate to be determined.

Table 4.5.3-1 - Heat emission from bare copper pipesW/m run of horizontal pipe (in sti ll air at 20oC)

Nominal pipediameter, mm

Uninsulated pipeper

oC

Uninsulated pipe per40

oC temp difference

(i.e. at 60oC delivery)

15 0.67 27

20 0.97 39

25 1.26 50

32 1.53 61

40 1.8 72

50 2.33 93

65 2.84 114

80 3.34 134

100 4.34 174

Source: AIRAH DA16 Application Manual Table 5-30E and ASHRAE 1999 ApplicationsHandbook Section 48, Table 2



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Note:

1. ASHRAE recommend for rule of thumb instances to utilise an average value of 60W/m for uninsulatedpipe.

2. Values approximately double when bare pipe work is exposed in a 2 m/s wind.3. Vertical pipe work emits heat at approximately a 10% higher rate.

Table 4.5.3-2 - Heat emission from insulated copper pipesW/m run of horizontal pipe (in sti ll air at 20oC)

Nominal pipediameter, mm

Insulated pipe per40

oC temp difference


R = 0.3


oC temp difference


R = 0.6


oC temp difference


R = 1.0

15 13.6 7.6 6.4

20 15.2 9.2 7.2

25 18.0 10 8.4

32 20.8 11.6 9.640 22.8 12.8 10.4

50 26.0 14.8 11.6

65 30.8 17.6 14.0

Source: Plumbing Engineering Services Design Guide 1988, UK Institute of Plumbing.

Note:

1. ASHRAE recommend for rule of thumb instances to utilise an average value of 30W/m for insulated pipe.2. R ratings are achieved as follows:

a. 0.3 m2.oC/W is achieved with 13mm closed polymer insulation

b. 0.6 m2.oC/W is achieved with 25mm closed polymer insulation

c. 1.0 m2

.o

C/W is achieved with 38mm fibreglass insulation

4.6 Outlet devices / terminal units

The selection of the outlet devices is usually beyond the control of the designer of the SHWsystem as the architect or end user stipulates them. However the SHW designer can havean input into energy saving features such as follows:

Consider installation of flow control devices in the distribution system to minimisewater flow rates at outlets to minimum requirements;

Discuss with the architectural team and end user in the design stages the benefits of

alternative equipment selections with more efficient energy ratings;

Generally, when specifying outlet devices consider low flow AAA rated devices;

Select devices with low energy consumption rates; and

Correctly size and locate Thermostatic Mixing Valves (TMVs) where supply watertemperature from the hot water system must be at 60oC and delivered at outlets atapproximately 42oC.



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4.7 Warm Water Systems

In instances where water can be supplied throughout a complex at say 45oC or lower warmwater systems can be utilised which are essentially the same as typical SHW systems withthe exception of the supply water temperature. The major advantage of these systems is theenergy savings that are achieved by avoiding any requirement to heat water to the

recommended 60

o

C and then cool it back down again at the outlet. It should be noted that inaged care and disabled facilities warm water temperature systems are stipulated.

The disadvantages are that Legionella flourishes in the temperatures at which warm watersystems operate and specialised disinfection systems are necessary. Systems such as UVdisinfection systems create additional maintenance issues and if not properly maintained willcreate a Legionella risk. UV systems also require specific flow rates, which will affect theselection of pumps. In addition warm water systems are required registration items by stategovernments, which adds an additional ongoing expense to the end user and needs to beconsidered in any life cycle analysis.



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5 SERVICES HOT WATER USAGE PROFILES

5.1 Introduction

The use of SHW in a particular building varies from season to season and day to day. In

Australia there are no public records of SHW water use and hence energy use.Consequently it is difficult to estimate how the energy use of a SHW system varies with time.

In order to enable comparisons to be made of different systems, SHW use profiles areproposed for the different BCA building classes. The respective profiles are based onmaximum hot water usage rates for the building class. The maximum rate would bedetermined for the number of terminal units.

5.2 Predicted SHW usage profi les

There is insufficient data available to enable seasonal and weekly profiles to be developedso only daily profiles for weekday and weekend use in each of the building classes wereestimated. It is proposed that these profiles then be applied to the SHW system throughout

the year.

They will not provide an accurate estimate of energy use but will enable comparisons to bemade between different systems.

The predicated usage profiles have been determined for a range of typical buildingclassifications. The profiles are tabulated in Appendix E.

The building classifications and types for which the profiles have been developed are:

Class 2 Apartments;

Class 3 Motels;

Class 5 Offices;

Class 6 Retail;

Class 7 Storage;

Class 8 Workshop; and

Class 9 Healthcare.



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6 SHW ENERGY SAVING OPTIONS AND ENERGYCONSUMPTION GUIDELINES

6.1 Energy Saving Options

The provision of energy saving options needs to be considered in the context of each of thefour key components of SHW systems as defined in Section 2.

6.1.1 Heat Transfer Equipment

Services Heating Water should be separate from any central heating water systemsfor supply of heating water to air conditioning systems or hydronic heating systems.

All storage vessels should be appropriately insulated to reduce standing losses.AS1056.1 defines requirements for maximum heat loss levels that are acceptablewith all new storage vessels.

To save energy from hot water expansion, heat traps or cold-water expansionvalves or expansion chambers should be provided. An amendment, Amdt 1, toAS/NZS 3500.4.2 is proposed as part of the energy efficiency measures for the BCAVolume 2 (Housing Provisions), which was issued in March 2002.

All hot water piping for domestic hot water systems should be insulated.

Instantaneous heating water systems are typically more energy efficient thanstorage systems. Where practical, instantaneous systems should be utilised in lieuof storage systems.

Equipment needs to be correctly sized for the expected loads. Both peak loads andtypical daily profiles need to be determined as accurately as possible.

Boiling water units are commonly oversized. Experience shows that with the quickrecovery time of boiling water units smaller units can be selected.

The utilisation of local boiling water units rather than distributed central systemsshould be investigated, as local BWUs provide a far more efficient form of hot waterdelivery.

Boiling water units and storage water units should be selected for maximum energyefficiency.

Timer control of heating systems should be incorporated to minimise standing heatlosses.

Gas fired heating sources should operate on electronic ignition and considerationshould be given to modulation of the gas flow.

Limit water temperature to the lowest permissible level. Most SHW systemstypically heat water to 60oC or greater and then it is mixed at the outlets for a finaldelivery temperature of only 30oC to 50oC. Provide stand-alone SHW systems toareas with very high water temperature requirements, i.e. 82oC to kitchens.

Locate the heating equipment as close to the terminal units as possible to minimisepiping lengths.



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In low use areas, i.e. sports facilities or kitchenettes, provide instantaneous systemsto avoid any storage losses and provide on/off control to ensure the system is onlyavailable when the space is utilised.

Select equipment with high levels of energy efficiency with high star rating that meetthe MEPS criteria.

Gas equipment is rated under an AGA scheme, which provides star ratings, basedupon annual gas consumption levels. A review of the current literature indicates thata minimum star rating of 3.0 stars for storage and gas boosted solar hot watersystems and 5.0 stars for instantaneous hot water systems should be considered.

Wherever possible look at utilising sources of waste heat as a preheating option forthe cold water.

Alternatives to the above are to install an energy efficient heat pump or to installsolar collectors to pre heat the cold-water inlet to a temperature of approximately35oC-40oC. A significant number of variations of this concept would have beeninstalled throughout Australia and their effectiveness / efficiency should be reviewed.

For a cost saving measure, designs have occasionally been developed which utilisean off-peak heater arrangement to preheat the cold-water inlet, and then threephase heating equipment would meet peak immediate load requirements. Whilstthis may have energy cost savings, further investigation would need to beundertaken to determine if it actually reduces energy consumption. An initialassessment would appear to indicate that this is not the case and at best that theconcept is energy neutral compared to a standard bank of HWCs. It appears thatoff-peak preheating and then heating before use systems should not be consideredas an energy efficient design option.

6.1.2 Heating Energy Source Consideration should be given to the use of solar hot water systems where

appropriate as these systems (if correctly installed, commissioned and maintained)provide the lowest greenhouse gas generation.

Generally solar power is both the most economical and results in the lowestgreenhouse gas emissions. Gas is considered as the next most greenhousefriendly fuel source and if it is Natural Gas it is relatively economical.

Day rate electricity is typically the most expensive energy source and is also thehighest in greenhouse emissions (unless generated in Tasmania or by any of theGreen Energy Sources now available from many of the power retailers throughoutAustralia)

A review of available fuel types to evaluate greenhouse gas emissions associatedwith each option should be undertaken as part of the evaluation.

If process water or other alternatives of waste heat exist, consider using heatexchanger type systems to take advantage of this free heating energy.

6.1.3 Distribution Systems

Circulating pumps should be controlled to only operate when required.

Dead legs in piping systems should be minimised and preferably eliminated totally.



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All hot water lines, including return water lines should be insulated. Minimumthermal insulation levels have been proposed in the recommended Amdt 1 to AS3500.4.2

Design the piping waste system to run grey waste though a storage vessel / heatexchanger to recover some of the waste heat which is usually never recovered

when hot water has been used. Provide pressure reduction devices in the system, to assist in limiting water flow

through outlets and to increase equipment life.

6.1.4 Outlet devices / Terminal uni ts

Selection of low flow fixtures and fittings is a critical area as any reduction in waterusage is a reduction in energy use. In addition reduced pipe sizes, which havereduced energy losses and are more economical to install, may be a secondarybenefit.

The use of a water flow management system, including flow restrictors and pressurereducing devices valves, is recommended.

The purchase of water-using equipment including dishwashers and washingmachines needs to be considered on the basis of their water efficiency. A selectionbased on AAA water consumption and a minimum four star energy rating arerecommended.

Install outlets with self closing mechanisms.

6.2 Energy Consumption Guidelines

The determination of the energy consumption of SHW systems must include the followingcomponents:

Storage vessel standing losses.

Piping system losses.

Delivery temperature, storage temperature and cold water makeup temperature.

Hot water demand from all fixtures.

Daily hot water usage profile.

Fuel source and heating systems efficiency.

Heating mechanism, i.e. instantaneous, storage or hybrid.

Circulating pump power usage and operating times.

Guidelines to enable estimates of energy consumption of SHW systems are provided below.

Storage vessel and boiling water unit standing losses are provided in Tables 6.2-1and 6.2-2 below.

Piping system heat losses are tabulated in Tables 4.5.1-1 and 4.5.1-2



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Delivery temperatures and seasonal cold water temperatures are provided inAppendix D and Section 7. Storage temperatures are typically recommended to be atthe minimum end of storage requirements where possible, i.e. 60oC, unless a warmwater system is being provided or delivery temperatures need to be higher.

The hot water demand for typical fixtures are supplied in Appendix D

Typical hot water usage profiles are available from Section 5 and Appendix E

Fuel greenhouse gas emissions and efficiency of various heating systems aretabulated in Tables 6.2-3 and 6.2-4.

Circulating pump power usage will be available from manufacturers data and theoperating times can be based upon usage profiles.

Table 6.2-1 - Electric Water Heaters, Maximum Heat Loss

1 2 3 4

Maximum heat loss, kWhr/24h (refer note 1)

Water heaters without an attachedfeed tank

Rated Hot Waterdelivery, (L)

Unvented (refernote 2)

Vented

Water heaterswith an attached

feed tank

25 1.4 1.4 -

31.5 1.5 1.5 -

40 1.6 1.6 -

50 1.7 1.7 -

63 1.9 1.9 -80 1.47 2.1 -

100 1.61 2.3 2.6

125 1.75 2.5 2.8

160 1.96 2.8 3.1

200 2.17 3.1 3.4

250 2.38 3.4 3.7

315 2.66 3.8 4.1

400 2.87 4.1 4.4

500 3.15 4.5 4.8

630 3.43 4.9 5.2

Source: AS1056.1-1991, amendment 3 1996 Table 2.1

Notes:

1. These values apply to water heaters with a single heating unit and may be increased by 0.2 kWh/24h foreach additional heating unit.

2. The values in Column 3 may be used instead of the values in column 2 for un-vented water heaterswithout an attached feed tank that are manufactured in Australia before 1

stOctober 1999 or imported

before 1st

October 1999.



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The values for un-vented water heaters without an attached feed tank may be increased by 0.2 kWh/24hfor each temperature sensor or temperature relief valve mounted on a hot-water fitting, but not for anyvalve on a cold-water fitting.

Table 6.2-2 - Boi ling Water Units, Rated Heat Loss

Rated Capacity Rated cupcapacity

Element kW Heat Loss(kWh/24h)

2L 10-14 1.5 1.12

3L 15-18 1.5 1.04

5L 30-35 2.4 1.50

7.5L 45-50 2.4 1.52

10L 60-75 2.4 2.03

15L 100-125 2.4 2.23

25L 150-190 3.6 2.71

35L 200-280 2.4 x 2 4.94

50L 300-490 3.6 x 2 5.71

75L 450-740 3.6 x 2 Note 1

100L 600-980 3.6 x 2 Note 1

Source: ZIP Product Guide, Technical Data dated 19/5/98

Notes:

1. Data was not available at time of printing.

2. Capacity and heat loss based on cold water at 20oC and supply temperature of 100

oC.

Table 6.2-3 - Heating Systems eff iciency

System Efficiency

Instantaneous gas heaters 80% - 85%

Electrical Storage water heaters 95% - 98%

Gas storage water heaters 62% - 80%

Heat pumps 300% - 450%

Note:

1. System efficiencies are related to the heat transfer equipment and ignore inefficiencies related to heatloss in piping network etc, as losses associated with the distribution network should be calculatedseparately.



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Table 6.2-4 - Fuel greenhouse gas conversion factors

Fuel Energy Content CO2 emissions (kgCO2/GJ)

Natural Gas Australian Average 39.5 MJ/m3 59.4

LPG 49.6 GJ/tonne or25.3 GJ/kL 59.4

Heating Oil 37.3 GJ/kL 69.7

Fuel Oil 40.8 MJ/L 73.6

Diesel 38.6 GJ/kL 69.7

Electricity (1999 values) 3.6 GJ/Mwhr 0.968

NSW/ACT 0.968

Victoria 1.467

Queensland 1.040

SA 1.109

WA 1.032

Tasmania 0.002

NT 0.756

Australian Average 1.051



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7 AVERAGE SEASONAL COLD WATER SUPPLYTEMPERATURES

AS2984 has identified four climate zones for Australia in which recommended cold watertemperatures have been established. Table 7-1 below details cold-water temperatures on a

monthly basis for each of the four climate zones.

Table 7-1 - Cold Water Temperatures OC

Month Zone 1 Zone 2 Zone 3 Zone 4

January 28 29 23 20

February 28 27 23 20

March 27 24 21 18

April 25 20 18 15

May 23 14 15 11

June 20 11 12 9

July 20 9 11 8

August 21 12 12 10

September 24 18 15 12

October 26 23 19 15

November 28 26 21 17December 28 28 22 19

Average 24.8 20.1 17.7 14.5

Source: AS4234-1994, Solar Water Heaters-Domestic and Heat pump-Calculation of energyconsumption Table A5

The State and Territory capital cities and major cities fall into the following Zones:

Zone 1: Darwin and Cairns;

Zone 2: Alice Springs;

Zone 3: Perth, Adelaide, Canberra, Sydney, Brisbane, Geraldton,Kalgoorlie and Coffs Harbour and

Zone 4: Melbourne and Hobart



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Rinnai published a range of cold-water temperatures, which differ marginally from those,identified in AS4234-1994 as follows:

1. Darwin - 20oC to 30oC (Zone 1)2. Cairns - 20oC to 35oC (Zone 1)3. Alice Springs - 0oC to 30oC (Zone 2)4. Perth - 18oC to 32oC (Zone 3)

5. Adelaide - 15oC (Zone 3)6. Canberra - 3oC to 25oC (Zone 3)7. Sydney - 12oC to 25oC (Zone 3)8. Brisbane - 20oC to 30oC (Zone 3)9. Geraldton - 20oC to 35oC (Zone 3)10. Kalgoorlie - 18oC to 32oC (Zone 3)11. Coffs Harbour - Not identified (Zone 3)12. Melbourne - 15oC (Zone 4)13. Hobart - 12oC (Zone 4)

Temperature zones as identified in AS4234 are noted adjacent for comparative purposes.

Between the two sources of information, it would appear that the generalised zonings in

AS4234 are not suitable in all cases. We would recommend the following variations:

For Canberra, we would recommend that it be considered as a Zone 4 location, asshould any highland areas.

Perth would appear more suited to category Zone 1, rather than the current Zone 3.

Brisbane, Geraldton and Kalgoorlie should be located in Zone 1, rather than Zone 3.



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8 RECOMMENDED BCA AND AUSTRALIAN STANDARDAMENDMENTS

A number of opportunities exist for implementing energy efficiency provisions in respect ofSHW systems in commercial buildings, i.e. Volume 2 - Class 2 to Class 9. The following

provides a number of potential recommendations, which could be included, either directly inthe BCA, or alternatively included in Australian Standards, that are referenced in the BCA.

Recent amendments to AS3500.4.2 now specify a number of mandatory minimum energyefficiency requirements for hot water supply systems. These amendments include:

Provision of insulation on cold water pipe between storage water heaters and theclosest valve;

The first 500mm of the outlet pipe or to an external heat trap to be insulated;

The primary flow and return pipes between a storage water heater and auxiliaryheaters to be insulated;

Vent pipes to 300mm above the working water level of the hot water system to beinsulated;

On systems with multiple hot water heaters, the whole hot water manifold and 500mmpast the hot water outlet branch from the last hot water heater to be insulated;

Hot water system pipe sections in specific locations to be insulated; and

All new or replacement hot water systems to be installed with a heat trap.

Some minimum amendments that are recommended for inclusion in the BCA include:

1. All hot water systems to be installed in accordance with the latest Section 6A

amendments to AS/NZS 2500.4.2;

2. All hot water pipe work and associated valves, strainers etc, to be insulated i.e. theamended AS/NZS 3500.4.2 does not require insulation of the entire heating waterpiping system;

3. Where hot water service areas require differing temperatures, i.e. kitchens at 80oCnominal and 60oC nominal to general amenities areas, separate heating watersystems or booster heaters shall be supplied to the high temperature areas, to avoidexcess heating for the areas with lower temperature requirements;

4. Storage water heaters to be designed to avoid (or minimise) water loss due toexpansion and any pipe work between the storage water heater and any expansiondevices to be insulated;

5. Heating water systems in commercial installations which do not require draw downovernight to be fitted with time control devices;

6. Any in-line water storage devices, in addition to the storage water heaters, to beinsulated;

7. Any hot water system which is utilised for space heating purposes shall be a separateheating system to the domestic hot water systems for potable water, unless theheating system is a wood fired storage system, solar or similar;

8. A minimum of triple A rated (as rated on the WSAA web site) showerheads andtapware to be installed;



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9. Generally a means of educating the end user that the use of infrequent energyconsuming systems such as spas, etc. or systems in holiday homes with infrequentusage should be shut down when the spaces are unoccupied. Alternatively thesystem should be fitted with mandatory (but over-rideable) time clocks to ensureautomatic shutdown when not in use;

10. Where alternative fuel systems to electricity are available, i.e. natural gas, that servea multitude of units etc. it is recommended that the lower greenhouse gas emissionfuel source be the preferred design solution. Instantaneous heaters are also moreefficient in many instances to storage water heaters. We are unsure at this stagehowever as to how it would be possible to mandate this as a requirement in aregulatory document such as the BCA, although they could be referenced in theperformance requirements. An option could be for a set of best practice design notesbe developed which could perhaps be referenced within the BCA.

In relation to the above, concessions could be given for water heaters which are solar or heatpump types due to their greater efficiency. However the potential does exist that a futurereplacement may be back to a standard storage hot water system and energy inefficiencieswill then occur. If these systems are installed their installation may need to be managed toensure that any replacement of heating water systems also be included under the BCAapproval process.

We also recommend the development of an additional standard that is then referenced in theBCA. This standard would be:

1. an Australian Standard for boiling water units, which will stipulate minimum thermalinsulation values and general minimum energy efficiency requirements



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APPENDICES

Appendix A: Building Forms

Appendix B: Standard SHW System Definitions and Features

Appendix C: Application Sizing Guides

Appendix D: Service Hot Water Sizing Guide

Appendix E: Usage Profiles

Appendix f: References



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Appendix A

Building Forms

The following building forms were developed by the ABCB Office and the Working Groups toprovide building shapes that are thermally representative of buildings of a particular class butof varying size.

Form A

total FECA 10,000 m2

total NLA 8,500 m2

Floors 10

aspect ratio 1:1

NLA/floor 850 m2

Length 31.6 m

Depth 31.6 m

floor-floor 3.6 m

Form B

total FECA 2,000 m2

total NLA 1,700 m2

Floors 3

aspect ratio 2:1

NLA/floor 567 m2

Length 36.5 m

Depth 18.3 m

floor-floor 3.6 m



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Form C

total FECA 1,000 m2

total NLA 950 m2

Floors 1

aspect ratio 1:1

NLA/floor 950 m2

Length 31.6 m

Depth 31.6 m

floor-floor 6.0 m

Form D

total FECA 500 m2

total NLA 475 m2

Floors 1

aspect ratio 5:1

NLA/floor 475 m2

Length 50.0 m

Depth 10.0 m

floor-floor 3.3 m

Form E

total FECA 200 m2

total NLA 190 m2

Floors 1

aspect ratio 2:1

NLA/floor 190 m2

Length 20.0 mDepth 10.0 m

floor-floor 3.3 m



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Appendix B

STANDARD SHW SYSTEM DEFINITIONS and FEATURES



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SHW PROVISIONS IN COMMERCIAL BUILDINGS

SHW System Appl ication

Storage

Instant-

an

eous

Control

Maximumpipe

lengthsCircula

pum

Centralised SHW Form A-Class 2, Form A-Class 5, Form B-Class 2, Form B-Class 5, Form B-Class 6,Form C-Class 6, Form C-Class 8, FormD-Class 5, Form D-Class 9,

no yes water temp. -water off

thermostat,pump - time

clock

50 to 80 m yes

Centralised StorageSHW

Form A-Class 2, Form A-Class 3, Form A-Class 5, Form B-Class 2, Form B-Class 3,Form B-Class 5, Form B-Class 6, Form B-Class 9, Form C-Class 6, Form C-Class9, Form D-Class 3, Form D-Class 5, FormD-Class 9,

yes no water temp. -storage tank

waterthermostat,pump - time

clock

50 to 80 m yes

Localised SHW Form A-Class 2, Form B-Class 2, Form B-Class 6, Form C-Class 6, Form C-Class8, Form D-Class 5, Form D-Class 6, FormD-Class 8, Form E-Class 2, Form E-Class3,

no yes water temp. -water off

thermostat

10 to 20 m no

Localised Storage SHW Form A-Class 2, Form A-Class 5, Form B-Class 2, Form B-Class 5, Form B-Class 6,Form B-Class 9, Form C-Class 6, FormC-Class 9, Form D-Class 5, Form D-Class 6, Form E-Class 2, Form E-Class 3,

Form E-Class 5,

yes no water temp. -storage tank

water thermostat

10 to 20 m no

16020 Revision 4


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SHW System Appl ication

Storage

Instant-

aneous

Control

Maximumpipe

lengthsCircula

pum

Hybrid Centralised SHW Form A-Class 2, Form A-Class 3, Form A-Class 5, Form B-Class 2, Form B-Class 3,Form B-Class 5, Form B-Class 6, Form B-Class 9, Form C-Class 6, Form C-Class8, Form C-Class 9, Form D-Class 3, FormD-Class 5, Form D-Class 9,

yes yes water temp. -water off

thermostat,pump - time

clock

50 to 80 m yes

Notes:

1. The hybrid version is the close-coupled instantaneous heat source fitted to storage systems.

2. Maximum pipe lengths are dependant upon available water pressures, suitable heater locations, pumping systerecommended allowable piping lengths are stipulated in any literature reviewed as part of this report

16020 Revision 4


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Appendix C

APPLICATION SIZING GUIDES


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Sizing Guide Commercial Applications

Application BCAClass

Outlet type Peak periods Peakspread(Hrs)

Hot water usage(L/person UNO)

Aged Homes 9C Showers 9:00am 3 hr 18L per patient

Residential 2 Showers 7:00am and6:00pm

1 hr 15L

2 Basins Variable 2L

2 Kitchen Sink 8:00am and8:00pm

hr 7L per sink full

2 Dishwashingmachine

8:00am and8:00pm

1 hr 10L per meal

2 Clothes washingmachine

variable 50L per week

Hotels/motels 3 Showers 8:00am 1 hr 18L per person,allow 1.5 people

per room

3 Dishwashing sinks 10:00am and10:00pm

2 hrs 6L per 3 coursemeal

3 DishwashingMachine

10:00am and10:00pm

2 hrs 180L per 2 hours

3 Glass washingmachines

Weekdays 3 hrs 55L per hour or

3 Glass washingmachines

Weekends 6 hrs 7L per 25 glasses

3 Clothes washingmachines

Variable 4 hrs 15L per person

Offices 5 General showers

rarely used

Variable 8 hrs 4 L per person

Retail - hairdressing 6 Basins Variable 4 hrs 4L per client

Retail take-away 6 Dishwashing sink 12:00 noon 2 hrs 3L per meal

Retail - restaurant 6 Dishwashing sink 9:00am, 12:00noon, 8:00pm

2 hrs 5.5L per 3 coursemeal

Retail - restaurant 6 Dishwashingmachine

9:00am, 12:00noon, 8:00pm

2 hrs 180L per 2 hrs

Retail - Laundry 6 Clothes washingmachine

Variable 8 hrs Allow 70L permachine per hr.

All All Baths Various 1 60L per bathMiscellaneous

Gymnasiums Showers Variable 4 hrs 20L per person

Factories light Showers 4:00 pm 1 hr 20L per person,assume 30% usage

Factories - heavy Showers 4:00 pm 1 hr 20L per person,assume 200%

usage


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Appendix D

SERVICES HOT WATER SIZING GUIDE

WATER FLOW RATES

Fittings Outlet Flow (L/s)

Hot water Cold water

Typical mixedwater

temperature oC

Typicalusage

period (min)

Bath 0.20 to 0.30 0.20 to 0.30 40 5

Cleaners Sink 0.30 0.30 55 - 60 0.5

Drinking Fountain - 0.03 Cold water only

Dishwashingmachine

0.20 to 0.30 0.20 to 0.30 55 1-2

Basin 0.10 0.10 35 0.5-1

Hose Cock - 0.20 to 0.30 Cold water only

Laboratory outlet 0.10 0.10 55 - 60 1-2

Stock pot 0.30 - 55 - 60 0.5

Shower 0.10 0.3 0.10 0.3 40 5-10

Toilet Cistern - 0.10 Cold water only 1.5

Washing machine small

0.20 to 0.30 0.20 to 0.30 60 4-5

Kitchen sink 0.20 0.20 55 1-2

Services Hot Water Provisions for Commercial Buildings

Documents