The installation of hot water supply for hotel

Deciding Factors:

Required Consumption

Peak Demands

Types of Installation

Required Storage Capacity

Methods of Heating Water

Insulation of Pipework

Further Planning

2All images and data credit to their respective owners

Types of Hot Water Supply

System

Localised

Instantaneous single points

Storage type single points

Centralised

Direct

Electric water heating

Gas storage heaters

Boiler-cylinder system

Instantaneous system

The multi-port

The water-jacketed tube

heater

The combined primary

storage unit

Indirect

With expansion vessel

Vented storage

Unvented storage

Others

Solar heating

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Localised Hot Water Distribution System

A single-point heater located above a sink that heats

up water.

Heat up using gas and electricity

Two main types, i.e.:Instantaneous Single Points Storage-type Single Points


○ Instantaneous Single Points

Does not require storage area

Heating process begins when desired

○ Storage Type Single Points

Have a capacity of no more than 15 litres

Heated by electric element until water has expanded enough to

discharge from discharge spout


Centralised Hot Water Distribution System

Water is heated in a hot storage vessel, boiler or small

gas circulator

Connected by supply pipework and circulatory pipework

Water temperature in storage vessel should not exceed

60ºC

Two main types, i.e.:

○ Direct Hot Water Supply

○ Indirect Hot Water Supply


○ Direct Hot Water Supply

Heats up water in storage cylinder and transfers heat directly to

the surrounding water

Precipitation of limestone might occur which

has a chance to clog the boiler and pipeworks

Only suitable to use in areas of soft water

Various types

- Electric Water Heating

- Gas Storage Heaters

- Boiler-cylinder system

- Instantaneous System

- a) Multi-Point

- b) Water-Jacketed Tube Heater (Thermal storage system)

- c) Combined Primary Storage Unit (CPSU)


Centralised

Direct

System

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owners

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CentralisedInstantaneous System

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○ Indirect Hot Water Supply

Consists of an expansion, a calorifier

(hot water storage vessel),

and a heat exchanger

Water from boiler in primary pipework

passes through cylinder containing

heat exchanger to heat up water

Closed circulation can prevent clogging

Secondary circulation is required to

prevent dead legs

Various Types:

- Indirect Hot Water System with

expansion valve

- Vented Storage Hot Water Supply

System

- Unvented Storage Hot Water Supply System


Indirect Hot Water

System with

Expansion Valve

Vented Storage Hot

Water Supply System

Unvented Storage Hot

Water Supply System



Solar Hot

Water

Supply

System


More complicated while required to install at

high rise building

Enormous piping system required

Few considerations

Type of hot water supply system to be installed

Materials for pipe used


Types of Pipe Material available

Copper

○ High thermal conductivity

○ Lower cost and high availability

Cross-Link Polyethylene (PEX)

○ Plastic pipe that able to withstand temperature up to

100ºC

○ Speeds up installation process since

it is flexible


owners 15

Polybutylene (PB)

○ Plastic resin material

○ Low cost and easily installed

○ Not resistant against oxidants

○ Poor chemical resistivity


owners 16

Two main choices of installing hot water storage

Huge storage tank to be installed on top of building

Installation of reasonable sized storage tanks every 10th

levels

Installation of zoning valve

Installation at main pipe each floor

before separated into every room

Allows easier maintenance


Monitoring Temperature of hot water

Larger scale of circulation in hotel which includes principal

loop, subordinate loops, and localized loops (tertiary loops)

Conducted at sentinel points

Carried out monthly to ensure hot water is supplied at suitable

temperature


Water Softening

Conducted at connection between cold water supply to hot water

system to prevent heavy deposit of scale

Heavier deposits can reduce flow significantly, cause impact of

efficiency of system and may lead to microbial colonization

Inspection of calorifiers

Inspection to be carried out internally by:

○ Removing Inspection hatch

○ Inspection on the initial flush for clarity, quantity of debris,

temperature

Should be carried out annually and frequency should increases as

indicated by risk assessment or result of inspection to be

unsatisfying


Chlorine Inspection

Chlorine is used for disinfection purpose

Suitable concentration range is 0.5 -1.0 mg per liter

Overdose will cause health issues to users such as skin infections,

irritations

Carried out annually

Water Sample Inspection

Water sample at final outlets should be collected randomly on a weekly

basis for inspection

To ensure hot water supply contains no contamination and every

element at suitable dosage

If result is unsatisfying, further inspection should be carried out on

entire system and essential repair should be conducted

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Comparison of Advantages between Indirect Water supply System &

Direct Water Supply System

Indirect System Direct System

•Separate circuit for water drawn off at

taps

•Water through the boiler can be drawn

off for the taps

•Used in hard water areas •Heat quicker

•Used when heating is combined within

system

•Sealed primary circuit can be pumped

or can circulate by natural convection

•Less maintenance cost •Adequate pressure on the main

•Saves the cost of a storage and

expansion cistern and associated

pipework


Advantages and Disadvantages of Unvented System

Advantages Disadvantages

•Provide hot water constantly at main pressure •Installation cost is higher than

vented system

•No requirement for cold water storage tank •Need specialist for installation

•Extra pipework for linking •Rely on automatic control

•Give greater flexibility to design of taps, mixers,

and shower heads

•Might run out of water

Advantages and Disadvantages of Vented System


•Less complicated design •Require cold water storage tank

•Easier installation

•Lesser cost for purchase and installation

•Can be either indirect or direct vented system


Advantages and Disadvantages of Conventional Storage Water Heater


•Low product and installation cost •Higher utility bill

•Available in a variety of sizes •Might run out of water

•Instant hot water supply •Storage space required

•Less durabililty

Advantages and Disadvantages of Tank-less Water Heater


•Energy saving •Limited output

•Longer lifespan •Expensive initial cost

•Compact size •Needs gas unit for best performance

•Durable


Advantages and Disadvantages of Solar Water Heater


•Runs on renewable energy source •High initial cost

•Lower utility cost •Complicated installation

•Suitable for tropical climate countries •High maintenance cost

•Non-polluting

Advantages and Disadvantages of Heat Pump Water Heater


•Big volume of hot water supply •High initial cost

•Long lifespan •Size of heat pump can be huge

•Low maintenance cost •Various grade of quality

•Anti freezing

•Safe and eco-friendly (no combustion)


Advantages and Disadvantages of Indirect Water Heater


•Efficient for home usage •Requires storage tank

•Saves energy

•Variety source of energy

•Efficient life span

Advantages and Disadvantages of Tankless Coil Water Heater


•Higher performance during cold

weather

•Inefficient for countries with warmer

climates

•Does not require tank


Air Locks

Air might enter the system through

cylinder vent and cause restriction

of water flow

To eliminate air locks,

○ sufficient pressure

is required to push air through the pipe

○ Installing vent points in pipes so air can escape through the

vents


Noises

Occur in high pressure systems

Occur due to fluctuations of water

flow which causes vibrations

To prevent occurrence of noises,

○ Pipes should not be in direct contact with building

○ Use rubber insulated clips to clip over pipes

○ Pipework should be fixed rigidly


Poor Water Flow

Occur due to air locks, clogged pipes,

mineral clogging in water tank or

tank-less coil


Insufficient Hot Water

Due to unsuitable size of cylinder or boiler,

excessive primary flow and return pipes,

leakage, air locks or poor quality of fuel used

May be due to mineral deposits

and blockage in water tank


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Leakage

Will result in loss of pressure

Occur due to corrosion of pipes or

thermal expansion in closed water system

Back siphonage

Backflow of water due to negative pressure

Occurs due to excessive demand of hot

water

May causes contamination of water and

health issue


Overheating and failure of heating

element

Faulty thermostats will cause the water

to

continue to be heated

Mineral deposits may build up on

heating

element and causing damages


owners 31

FUTURE IMPROVEMENT Installation of extra tanks

Descale or replace heating elements

Installation of high efficiency water heaters

Comparison of choices for the most suitable system to be

installed

Installation of hot water pump and higher efficiency loop

system

Installation of a larger cold feed pipe or raising the storage

cistern to increase the water flow pressure.


Operating since 2010

84 rooms

Unique in-campus

hotel design

Localized Instantaneous Water Storage Heater

System was used

Water storage heater installed in each room

Capable of holding 135 liters of water

Runs on electricity


Standard Installation of Electrical Storage Heater34


Blue ABS pipe carriescool water

Copper pipe carries hotwater to draw off points

Stored water heated byelectric element

Cool water replace the discharged hot water

Standard temperature is between 60ºC to 75ºC

Temperature is obtained using thermostat

Problems Electricity supply might trip due to overheating

Faulty thermostat will fail to detect temperature and causes water to be overheated


Future Improvement Suggestion For Ruemz

Hotel @ Taylor’s University Lakeside Campus

Replacing using Solar Water Heating System

○ Uses solar energy

Free and renewable resource

○ Suitable for tropical countries like Malaysia

○ Boiler can be installed as a back-up

○ Can be integrated into existing hot water supply system

○ Suitable for installation at hotels

Higher levels which can receive direct sunlight

○ Reducing usage of fuel to heat up water

○ Higher efficiency than most water heating system


Operating since July, 1983

Total of 726 guestrooms

and suites

Located at 2 Charoen

Krung Soi 30, Siphya,

Bangrak, Bangkok, 10500, Thailand


Originally, it uses hot water supply system that’s

made up of 2 boilers

Each boiler capable of producing 5 tons per hour

Average consumption about 2,000 liter per day

5 hot water generators were installed

Temperature controlled at around 55ºC

Average consumption about 95m3 per day at

70% occupancy


Rising of price of fuel causes them to switch to

Solar Water Heating System

Solar Water Heating System consists of:

360m2 flat plate solar collectors

Two hot water storage tanks

○ Each tank has a capacity of 23,000 liters

Circulation pumps

Control System

Capable of producing 24,000 liters of water at

an average temperature of 55ºC per day


Differential thermostat is used to determine the usage

of circulation pumps

Hot water from storage tank flows into hot water

generators and discharges into hot water piping system

5 units of heat pump for additional hot water supply are

installed to ensure enough supply

Each unit capable of producing 2,000 liter of hot water at

50ºC

Operates when temperature in storage tank is below a set

point, usually during evening and night


Schematic Diagram of Solar Water Heating System Used

Heat Pumps Installed at Rooftop


The installation of hot water supply for hotel

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