dhp.pdf

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DHP-1

COMMERCIAL PRODUCTS

THE DHPTM SERIES

Dehumidifiers Heat PipesTM

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DHP-2

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DHP-3

DEHUMIDIFIER HEAT PIPES IN AIR CONDITIONING

Made with Copper Tubes for Reliability and Longevity

Highest Heat Transfer Efficiency

Low Air Pressure Drop

Tremendous Increase in Moisture Removal Capacity

Drier Supply Air

Energy Savings

Passive Operations

Require Only Periodical Maintenance

Rapid Payback

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DHP-4

DHP Installation

DEHUMIDIFIER HEAT PIPES IN AIR CONDITIONING

HPT dehumidifier heat pipes are usually installed in A/C units in a wrap-around configuration. The firstsection of the heat pipe module precools the entering air before it goes through the cooling coil. Theprecooled air thus approaches the cooling coil at a lower temperature allowing it to be overcooled by thecooling coil before being reheated by the second heat pipe section. The function of the heat pipe isperformedpassively without a compressor or any mechanical moving parts. The heat pipe is activated bythe difference of temperatures between entering air and after the cooling coil.

Dehumidifier heat pipes can be installed around chilled water cooling coils as well as direct expansion(DX) cooling coils.

Typical Installation of a Wrap-Around Heat Pipe in an Air Handler Unit

Methods of Installation

A. Factory Installation

New: A/C units are shipped by the manufacturer/contractor to the HPT facility in Gainesville, Floridawhere they are factory retrofitted and then shipped to the final destination. Depending on the quantityand the size of the units, most systems are retrofitted in ten (10) working days or less. Specialsystems and larger sizes may take longer.

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DHP-5

B. Field Installation

Units are retrofitted in the field by HPT certified heat pipe technicians. Air conditioning units are fieldinspected with all measurements taken; heat pipes are then designed and built to fit. A field

installation crew from HPT is sent to install the heat pipes. Heat pipes have been field installed bythis method in many locations of the United States, including Hawaii, as well as the Caribbean, Asia,and South America.

C. Pre-FabricatedDHP-U (U-Framed Heat Pipes)

These are U-Framed heat pipes that are made-to-fit units in the field or at an air handlermanufacturer's facility. They come completely pre-charged and sealed and ready for sliding into anair handler. Applications of this type are limited to specific size units and some OEMs. Custom-builtU-Framed heat pipes to fit specific equipment are also available. See Product Section for moredetails.

D. DHP-M (Monoflat Heat Pipes)

Monoflat heat pipes are primarily designed to fit into ductwork when retrofitting inside of the A/C unitis not feasible. Typically, the DHP-M comes pre-charged, sealed and ready for installation. Theowner hires a local contractor to install these heat pipes. Their installation requires no specifictraining, but may require some ductwork modification. Different duct configurations will requiredifferent flat heat pipes. See Product Section for more details.

Installation Requirements

A typical two-row heat pipe installation system requires 4of space on both sides of the cooling coil. The heat pipeswill be mounted flange-to-flange on the cooling coil. Ifrequired, and where available, heat pipes can be mountedin spacer sections provided by the manufacturer of the A/Cunit.

One-row systems require approximately 2 1/2" minimum ofspace on both sides of the cooling coil.

Three-row systems require 5 on both sides. Four-rowheat pipe systems require 6 on both sides of the coolingcoil, and so on.

Some OEMs prefer to send the bare cooling coil to save

on freight costs. Heat pipes will then be mounted directlyon the cooling coil. The manufacturer then installs thecomplete assembly in their unit.

Heat pipes mounted on coolingcoils for OEM applications

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DHP-6

When considering fitting heat pipes into a unit, keep in mind the following points:

1) Field Instal lat ion

Since heat pipes connecting tubes are always at the end of the cooling coil that does not have manifolds

(see diagram), there has to be room at that end for installation of connecting tubes, evacuation, andcharging. In the case of controllable heat pipes, the room is needed for valve wiring and maintenancealso.

2) Factory Instal lat ion

As in Field Installation, controllable heat pipes need room for wiring and solenoid valves servicing afterthe A/C unit is installed on-site. The non-controllable heat pipes have no moving parts on the connectingtube end. Access room to that end is recommended but not critical.

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DHP-7

Types of Units That Can Be Fitted with Heat Pipes

Wrap-around dehumidifier heat pipes can be installed in almost any A/C manufacturer's units. HPT hasextensive heat pipe installation experience with equipment manufactured by Carrier, Lennox, McQuay,Trane, York, Addison, Aaon, Air Enterprises, Florida Heat Pump, Season's Four, Water Furnace and

others. If in doubt, check with your local HPT representative or with the HPT main office for installationrequirements of specific units.

Penthouse Units

Air Handlers Fan Coils

Manufactured under license from HPT

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DHP-8

Types of Units That Can Be Fitted with Heat Pipes

Packaged Units

PTACs

Available only from General Electric, manufactured underlicense from HPT.

Built-up Custom Units

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DHP-9

Dehumidifier Heat PipesTM

Features and Benefits

Design Features

Versatile

Dehumidifier heat pipes can be designed to fit almost any size of air handler. The amount of precool andreheat can be adjusted by correctly selecting the number of tube rows and the fin density. Dehumidifierheat pipes can be installed around cooling coils in air handlers, in packaged air conditioning units, and inductwork.

Low Maintenance

Since heat pipes have no moving parts and are activated only by the difference in temperatures acrossthe cooling coil, they need very little attention. Only periodical cleaning like any other air conditioningcoils is required.

Long Li fe

Since heat pipes are sensible energy transfer devices, they stay dry most of the time. Galvanic corrosionis not an issue in most applications. (In corrosive environments, coil coatings are offered). Heat pipestypically outlast the cooling coils of the air conditioning systems in which they are installed.

Compact

Since dehumidifier heat pipes wrap around the cooling coils, no additions to the air conditioning units arenormally needed. Typically little room is needed inside A/C units to accommodate the heat pipes.

Total ly Passive

The standard dehumidifier heat pipes are totally passive with no moving parts.

Control labi l i ty

Controllability of heat pipes is offered as an option. This allows the operator to turn the heat pipes on-offor modulate their performance. Only HPT offers this feature.

Quali ty

With the Heat Pipe Technology name, you are guaranteed the best product. Product testing is part of thestandard procedure to ensure top quality.

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DHP-10

Benefits

Increase Moisture Remo val of A/C Units

The first section of the heat pipe module precools the entering air. This causes the approach temperature ofthe air to the cooling coil to be lower. The result is, that as the air leaves the cooling coil, it is colder with alower dew point and with less moisture in it. Depending on the design of the heat pipes, the cooling coil canbe made to extract over 100% more moisture than one without heat pipes.

Dryer Supp ly Ducts

After leaving the cooling coil, the air is reheated by the second heat pipe section. This lowers the relativehumidity of the supply air. In a typical system, the relative humidity is lowered from nearly 100% leaving thecooling coil to approximately 70% leaving the second heat pipe section. This is in keeping with ASHRAEStandard 62-1989 which warns that if duct relative humidity exceeds 70%, fungal contamination can occur.

Humidity Control

Buildings in humid climates frequently encounter serious humidity problems that need to be addressed. Otherbuildings used for specific purposes like hospitals, certain food processing plants, and some manufacturingplants require humidity to be kept at a low level. HPT dehumidifier heat pipes are usually the most efficientmethod of humidity control in these situations. By helping the A/C system remove more moisture from theair, the required humidity levels can be easily achieved.

Energy Savings Through Passive Reheat

Since heat pipes provide reheat by utilizing the heat from the entering air, there is no requirement for activereheat and there is no net heat added to the space. Using heat pipes to replace active reheat results insubstantial savings. A payback of one year may be achieved when electric reheat is replaced withdehumidifier heat pipes.

Energy Savings w ith Higher Thermostat Setting

As the relative humidity in a building is reduced by the addition of heat pipes, the thermostat can be set to ahigher temperature while maintain the same level of comfort and save energy.

Equipment Savings Through Downsizing

To cope with high humidity loads, the most frequently used technique is to oversize the A/C unit and thenreheat the overcooled air. This results in high operating cost as well as initial equipment cost. If dehumidifierheat pipes are used, oversizing and active reheating can be avoided. With a chilled water system, HPT heatpipes allow the designer not only to reduce the size of the cooling coil but also reduce the chilled water

requirement, thus a smaller chiller unit can be used instead.

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DHP-11

Products Available

1. DHP: Factory or Field Installed Wrap-Around Dehumidifier Heat Pipes

Wrap-Around Dehumidifier Heat Pipes installed in coil sections

Features

Factory or field installed wrap-around dehumidifier heat pipes are the most versatile dehumidifier heat pipes.They can be installed around the cooling coil in most any air conditioning unit to provide the dehumidifyingbenefits of reheat with no reheat cost. Highly experienced HPT technicians install the heat pipes at both theHPT factory and in the field assuring excellent installation and proper operation.

Applications

Typically installed in A/C manufacturers' catalog units: Chilled water air handlers and DX equipment, bothpackaged and split systems.

Model Designation

Wrap-around dehumidifier heat pipes are designated as

DHP-nR

where "n" is the number of rows of each heat pipe section. For example, a two-row heat pipe system (2 rowsprecool and 2 rows reheat) designation is DHP-2R.

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DHP-12

2. DHP-U: U-Framed Dehumidifier Heat Pipes

Features

These units are completely fabricated at the HPT factory and can be installed around a cooling coil withoutassistance by HPT technicians. They can be slid into place horizontally or lifted into place from above.

Applications

Typically installed by custom A/C manufacturers around chilled water cooling coils.

Model Designation

U-Framed dehumidifier heat pipes are designated as

DHP-U-nR

where "n" is the number of rows of each heat pipe section. For example, a two-row U-framed heat pipemodule (2 rows precool and 2 rows reheat) designation is DHP-U-2R.

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DHP-13

3. DHP-B: Combination Coils

Combo Coils (Dehumidifier Heat Pipes with cooling coil) installed inhorizontal air handler with vertical discharge.

Features

The combination of wrap-around dehumidifier heat pipes and a cooling coil are all in one coil pack. Allowsinstallation of dehumidifier heat pipes and a cooling coil as a single unit. The heat pipes are circuited andcharged and ready for operation. The cooling coil is fabricated according to the customer's specificationswith appropriate headers and fittings.

Application

Widespread uses. Can be installed in both chilled water air handlers and direct expansion (DX) equipment,both packaged and split systems. Typically used by custom A/C manufacturers and by contractors for unitrefurbishment when both a new cooling coil and dehumidifier heat pipes are being supplied. In this case theCombo Coil can be considered a "drop-in" replacement for the cooling coil as well as adding heat pipes.

Model Designation

Combo coils with dehumidifier heat pipes are designated as

DHP-B-nR

where "n" is the number of rows of each heat pipe section. For example, a two-row heat pipe combo coil (2rows precool and 2 rows reheat) designation is DHP-B-2R.

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DHP-14

4. DHP-C: Controllable Dehumidifier Heat Pipes

Heat pipe circuits shown are conceptual. Typical heat pipe systems are comprised

of multiple circuits. Consequently, multiple valves are used for control.

Features

Controllable dehumidifier heat pipes are designed to give the user the flexibility to modulate heat pipeoperation. When the weather is exceptionally warm with a high demand for sensible cooling, controllabledehumidifier heat pipes can be turned off in several stages, converting the extra latent cooling capabilityafforded by the heat pipes temporarily to assist in bearing the high sensible load. The percentage of thecooling effort required for the latent load is generally highest at part load conditions. As the outsidetemperature rises, the latent load may also increase, but the latent percentage of the total tends todecrease. Thus, backing off the heat pipe performance can boost the sensible capacity when needed andstill meet the latent cooling needs.

Heat pipe control is achieved through the use of multiple solenoid valves. The number of valves in eachsystem will depend on the size of the heat pipes. The number of solenoid valves opened or closed can becontrolled by a signal from a temperature controller or humidity controller or the valves can be operatedmanually when manual valves are used.

Applications

Typically used for applications where there is limited cooling capacity or where dehumidification needs to beclosely controlled. The connections between the heat pipe precool module and the heat pipe reheat moduleare normally made at the end of the cooling coil that is opposite from the chilled water or refrigerantconnections. Because the controllable heat pipe solenoids are installed in the heat pipe connections, theengineer should ascertain that there is accessibility space on the side of the A/C unit where the solenoidsare located.

Model Designation

Controllable dehumidifier heat pipes are designated by one of the following:

DHP-C-nR Controllable Wrap-Around Dehumidifier Heat PipesDHP-UC-nR Controllable U-Framed Dehumidifier Heat PipesDHP-BC-nR Controllable Combo Coil Dehumidifier Heat Pipes

where "n" is the number of rows of each heat pipe section.

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DHP-15

5. DHP-M: Monoflat Heat Pipes

Features

Does not require close proximity to a cooling coil for installation. Monoflat Heat Pipes can be easily re-installed if alterations are made to the A/C system. A drain pan under the heat pipes with provision fordischarging the condensate is normally recommended.

Applications

Typically installed in ductwork. The reason may be one of the following:1. The A/C unit does not have enough space for installing wrap-around heat pipes.2. The A/C unit has passed its prime with limited remaining life.3. The customer wants to be able to install the heat pipe, using a local contractor.

Model Designation

Monoflat dehumidifier heat pipes are designated as

DHP-M-nR

where "n" is the number of heat pipe rows.

Rooftop unit with front return and supply

Reheat

Precool

He

atPipes

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DHP-16

This configuration is not suitable for100% outside air systems due tocondensation and drainageproblems.

This configuration is notsuitable for 100% air intakedue to drainage problems.

Side-by-side vertical air streams

Over and under horizontal air streams withheat pipes in vertical plane

Side-by-side horizontal air streams

Note: 1) Access door recommended to inspect the heat pipe after installation.2) Air must be filtered before passing through the heat pipes.

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DHP-17


TYPICAL SPECIFICATIONS

Standard Wrap-Aroun d Dehum idifier Heat PipesTM

1.0 GENERAL

Air Handler(s) Packaged Air Conditioning Equipment shall be equipped with Dehumidifier HeatPipes supplied by Heat Pipe Technology, Inc. to precool the return/fresh air and reheat the supply airin a wrap-around configuration. The precool Heat Pipe heat exchanger shall be located immediatelybefore the cooling coil and the reheat Heat Pipe heat exchanger shall be located immediately afterthe cooling coil. Both Heat Pipe modules shall be inside and integral to the equipment cabinet. Theinterconnecting piping between the Heat Pipe modules shall be located within the assembledaccess/coil/access sections if possible. If not, the piping shall be external, but located within aremovable, insulated galvanized steel enclosure. When possible, all interconnecting piping shall belocated at the end of the cooling coil opposite from the coil header and piping connections. Anydeviation from the specifications must be approved by the engineer no less than ten days prior to theproject bid date. No consideration of alternates will be given after that time.

1.1 OPTIONAL HEAT PIPE LOCATION FOR MODULAR AIR HANDLERS ONLY.

To facilitate access between the cooling coil and the Heat Pipe modules, the air handler cooling coilsection(s) shall be supplied with two (2) factory installed blank access sections located immediatelybefore and after the cooling coil section. Each access section shall be provided with an integralcondensate drain pan and drain pan connection of the same construction as specified for the coolingcoil. The precool Heat Pipe module shall be located within the access section before the cooling coilsection and the reheat Heat Pipe module shall be located within the access section after the cooling

coil section.

1.2 OPTIONAL CONTROL VALVE FEATURE. All or a portion [SPECIFY] of the Dehumidifier HeatPipe circuits shall be equipped with solenoid operated control valves to control the operation of the

circuits. The electrical power required by the solenoid valves shall be 24 VAC 120 VAC. Thesolenoid valves shall be wired to a terminal block within a NEMA 12 enclosure located on the exteriorsurface of the equipment cabinet. All additional wiring, relays, transformers, etc. necessary tointerface with the control system manufacturer's components and power supply shall be providedand installed by others. Closing of a valve shall inactivate the Heat Pipe circuit in which it is installed.

The valves shall be: normally open normally closed. The control valves shall be groupedsuch that each group of valves shall control a designated fraction of the Heat Pipe circuits. With allcontrol valves open, the Dehumidifier Heat Pipe assembly will operate at full capacity. If all the

circuits are equipped with control valves, then closing all the valves will stop all Heat Pipe operation.

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DHP-18

Standard Wrap-Around Dehumid ifier Heat PipesTM (continue)

2.0 The Heat Pipe supplier shall have a minimum of 3 years of experience designing and installing HeatPipes specifically for dehumidification applications.

2.1 The tubes shall be copper, of specific design for heat pipe application, permanently expanded ontothe fin collar to form a firm, rigid, and complete pressure contact at all operating conditions. Theindividual Heat Pipe modules shall be made of UL listed components. Aluminum tubes will not beallowed.

2.2 The fin surface shall be continuous plate type aluminum copper fins of specific design toproduce maximum heat transfer efficiency for heat pipe applications. Airside pressure loss shall beas given on the schedule or otherwise specified. Fin density and the number of rows of tubes shallbe as specified.

The Heat Pipe modules shall have an optional protective coating.

2.3 Heat transfer fluid shall be classified as Safety Group A1 in BSR/ASHRAE Std 15-1989 R.

2.4 Heat Pipe capacities, entering and leaving dry and wet bulb temperatures, and face velocity shall beas specified.

2.5 The Heat Pipes shall be installed as shown on the submittal drawings.

2.6 Frames, mounting structure, and drain pan extensions (if required) shall be minimum 20 gauge

galvanized steel stainless steel.

2.7 Heat Pipe interconnecting piping and circuitry shall be as specified by Heat Pipe Technology design.Each circuit shall be individually processed, charged, hermetically sealed and tested.

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DHP-19

U-Framed Wrap-Aroun d Dehum idifier Heat PipesTM

1.0 Air Handler(s) shall be equipped with Dehumidifier Heat Pipes supplied by Heat Pipe Technology,Inc. to precool the return/fresh air and reheat the supply air in a wrap-around configuration. TheDehumidifier Heat Pipes shall be pre-fabricated in a U-Framed arrangement comprised of a precool

Heat Pipe and reheat Heat Pipe heat exchanger together in one assembly such that the assemblymay be installed into an air conditioning unit with the legs of the U-Framed unit on either side of thecooling coil of the air conditioning unit. The U-Framed assembly shall be configured such that theprecool Heat Pipe shall be located immediately before the cooling coil and the reheat Heat Pipe shallbe located immediately after the cooling coil. The interconnecting piping between the Heat Pipemodules shall be located within the U-Framed unit. Any deviation from the specifications must beapproved by the engineer no less than 10 days prior to the project bid date. No consideration ofalternates will be given after that time.


2.1 The tubes shall be copper, of specific design for heat pipe application, permanently expanded onto

the fin collar to form a firm, rigid, and complete pressure contact at all operating conditions. Thesubmittal shall include evidence that the individual Heat Pipe modules are made of UL listedcomponents. Aluminum tubes will not be allowed.




2.4 Heat Pipe capacities, entering and leaving dry and wet bulb temperatures, and face velocity shall be

as specified.

2.5 The frame shall be minimum 20 gauge galvanized steel stainless steel.

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DHP-20

Wrap-Around Dehumidifier Heat PipesTMwith BoostTM

1.0 GENERAL

Air Handler(s) Packaged air conditioning equipment shall be equipped with Dehumidifier HeatPipes supplied by Heat Pipe Technology, Inc. to precool the return/fresh air and reheat the supply airin a wrap-around configuration. When the chilled water Boost Coil is turned on, additional cooling issupplied to the leaving air. The precool Heat Pipe Heat exchanger shall be located immediatelybefore the cooling coil and the reheat Heat Pipe heat exchanger shall be located immediately afterthe cooling coil. The Boost Coil shall be an integral part of the reheat Heat Pipe heat exchanger.Both Heat Pipe modules shall be inside and integral to the equipment cabinet. The interconnectingHeat Pipe tubing between the Heat Pipe modules shall be located within the assembledaccess/coil/access sections if possible. If not, the tubing shall be external, but located within aremovable, insulated galvanized steel enclosure. When possible, all interconnecting Heat Pipetubing shall be located at the end of the cooling coil opposite from the coil header and pipingconnections. The chilled water connections to the Boost Coil shall be located at the same end as thecooling coil header.

1.1 OPTIONAL HEAT PIPE LOCATION FOR MODULAR AIR HANDLERS ONLY.

To facilitate access between the cooling coil and the Heat Pipe modules, the air handler cooling coilsection(s) shall be supplied with two (2) factory installed blank access sections located immediatelybefore and after the cooling coil section. Each access section shall be provided with an integralcondensate drain pan and drain pan connection of the same construction as specified for the coolingcoil. The precool Heat Pipe module shall be located within the access section before the cooling coilsection and the reheat Heat Pipe module shall be located within the access section after the coolingcoil section.


2.1 The tubes shall be copper, of specific design for heat pipe application, permanently expanded ontothe fin collar to form a firm, rigid, and complete pressure contact at all operating conditions. Thesubmittal shall include evidence that the individual Heat Pipe modules made of UL listedcomponents. Aluminum tubes will not be allowed.



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DHP-21

Wrap-Around Dehum idifier Heat PipesTM

with BoostTM

(continue)



2.5 The Heat Pipes shall be installed as shown on the submittal drawings.

2.6 Frames, mounting structure, and drain pan extensions (if required) shall be minimum 20 gauge

galvanized steel stainless steel.

2.7 Heat Pipe interconnecting piping and circuitry shall be as specified by Heat Pipe Technology design.Each circuit shall be individually processed, charged, hermetically sealed and tested.

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DHP-22

Mono flat Dehumidifier Heat PipesTM

1.0 Air Handler(s) Curb Ductwork shall be equipped with Dehumidifier Heat Pipes supplied byHeat Pipe Technology, Inc. to precool the return/fresh air and reheat the supply air in a planeconfiguration. The Heat Pipe shall installed such that the return/fresh air shall pass through one sideof the Heat Pipe for precooling immediately prior to passing through the cooling coil. After leavingthe cooling coil, the air stream shall immediately be directed through the other side of the Heat Pipefor reheating. Any deviation from the specifications must be approved by the engineer no less than10 days prior to the project bid date. No consideration of alternates will be given after that time.

2.0 The Heat Pipe supplier shall have a minimum of 3 years of experience designing Heat Pipesspecifically for dehumidification applications.

2.1 The tubes shall be copper, of specific design for heat pipe application, permanently expanded ontothe fin collar to form a firm, rigid, and complete pressure contact at all operating conditions. Theindividual Heat Pipe modules shall be made of UL listed components. Aluminum tubes will not beallowed.





2.5 Frame shall be minimum 20 gauge galvanized steel stainless steel.

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DHP-23

Selection Procedure

The Heat Pipe Computer Software developed and copyrighted by HPT is designed for selecting and

sizing HPTs dehumidifier wrap around heat pipes. Follow instructions in the accompanying manual toload and run. Contact your local HPT representative for any questions.

Manual Procedure:

A. Psychrometrics

The designer should first have an understanding of the psychrometrics of Dehumidifier Heat Pipes beforespecifying them. Fig. DH01 gives psychrometric plots of the cooling coil in a packaged DX system both withand without Dehumidifier Heat Pipes. The plots illustrate the performance of an actual packaged DX systemmade by a major A/C manufacturer. The performance data was determined using the manufacturer'spublished software.

The entering air temperature is shown at point 1 as 80FDB/67FWB. Without heat pipes, cooling starts atpoint 1 and continues to point 3 with a leaving condition of 59.0/57.3 and 90.5% RH. If Dehumidifier HeatPipes are installed such that there is 8.0 heat pipe precool and 8.0 heat pipe reheat, then the process startsagain at point 1 and continues through points 2, 3, and 4 with a leaving condition of 64.0/57.8 and 69.2%RH.The results of adding the Dehumidifier Heat Pipes in this particular case are as follows:

1. Reheat is supplied with no additional energy cost except for a little additional fan energy. Theprecool represents the additional cooling needed to compensate for the reheat. The precool is alsosupplied with no additional energy cost. For the particular example, if electric reheat were usedinstead of heat pipes, the reheat cost would be about 87% of the net cooling cost and the precoolwould be about 30% of the net cooling cost for a total premium of 117%.

Over-cooled

Dry andComfortable

Warm &

Humid

Increased Condensate

Pre-cooled

PrecoolHeat Pipe Cooling Coil

ReheatHeat Pipe

12

3

4

T1 DB/

T1 WB

T2 DB/

T2 WB

T3 DB/

T3 WB

T4 DB/

T4 WB

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15

20

25

30

35

40

45

50

50

55

45

40

35

30

25201510

6090F

80F

75F

80F

75F

85F

SPECIFIC

VOLUME(C

U.FT.PERLB.DRYA

IR):

15

14.51

3.5

13.0

12.5

70F

70F

.002

.004

.006

.008

.010

.012

.014

.016

.018

.020

.022

.024

.026

.028

120

115

110

105

100F

DRYBULBTEMPERATURE

95

90

85

80

75

70

65

60

55

50

45

40

35

65F

60F

ENTHALPY (h) - BTU PER POUND DRY AIR

ENTH

ALPY

(h)-

BTU

PER

POUND

DRY

AIR

HUMIDITYRATIO

(w)-poundsmoistureperpounddryair

55F

50F

55F

50F

45F

40F

40F

45F35F

35F

30F

25F

10%RELATIVE

HUMIDITY

20%

30%

40%

50%

60%

90%

1000

500

0

-1000

-2000

SENSIBLEHEATRATIO

ENTHALPYHUMIDITYRATIO

h

w

1500

2000

3000

5000

-0.1

-0.2

-0.3

-0.4

-0.5

-1.0

-2.0

-4.0

-8.0

-

8.04.0

2.0

1.0

00.

1

0.2

0.3

0.4

0.5

0.6

0.8

1.0

Technology, Inc.Heat Pipe

4340 N.E. 49th Ave., Gainesville, Florida 32609

Phone:Fax:

E-mail:

(352) 367-0999

[email protected](352) 367-1688

Fig DH01: Psychrometric Chart showing predicted performance of

T = 8FPRECOOL

12

3 4

30

SHR=0.

59WITH

HEATPI

PE

SHR=0.75WITH

OUTHEATPIPE

T = 8FREHEAT

Dehumidifier Heat Pipes installed in a specific packaged

DX system sold by a major A/C manufacturer.

85FWETBULBTEMPERATURE

1. Entering Air: 80.0Fdb, 67.0Fwb

2. After Precool Heat Pipe: 72.0Fdb, 64.4Fwb

30. After DX coil (no heat pipe): 59.4Fdb, 57.5Fwb

3. After DX coil (with heat pipes): 56.0Fdb, 54.9Fwb

4. After Reheat Heat Pipe: 64.0Fdb, 57.9Fwb

DXCOOLIN

G

WITHO

UTHEATPIPE

PRECOOL

REHEAT

DX COOLING WITH

HEAT PIPES

80.0/67.0

72.0/64.4

56.0/54.959.4/57.5

64.0/57.9

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DHP-25

2. The SHR (sensible heat ratio) is reduced from 0.75 to 0.59. This will more closely match thecooling equipment SHR with the load SHR for humid environments.

3. For equal amounts of sensible cooling, the moisture removed with Dehumidifier Heat Pipes in thisparticular example figures to be 205% of the moisture removed without heat pipes (an

improvement of 105%).

4. The relative humidity of the leaving air is reduced from over 90% to less than 70%. This is inkeeping with ASHRAE Standard 62-1989 which warns against duct relative humidity of over 70%RH as being conducive of fungal contamination.

5. With lower humidity in the space, the thermostat may be raised to provide actually better comfortconditions at a higher temperature. This can provide additional savings, not only in the cost ofoperating the A/C equipment, but typically much more savings are experienced in the preservationof the building, its furnishings, the carpet, etc.

6. Better health is promoted with relative humidity reduced to about 50%. This benefit is of course soimportant that no price can be applied to it.

7. The size of new A/C equipment can be reduced by 30% compared to the tonnage required tohandle the cooling plus active reheat.

B. Existing Equipment

First determine the cooling coil entering and leaving dry bulb and wet bulb temperatures and the airflow ratein CFM. Take several temperature readings both for the entering air and for the leaving air. Average them toget representative figures. Make sure that the leaving air temperatures do not include blower heat in draw-through units. Likewise, in blow-through configurations, take readings after the blower. When taking thetemperature readings, the cooling coil should be running at the design conditions that have been selected forapplying the heat pipes. For instance, you may want to be sure that the water modulatory valve is at thecorrect opening in a chilled water system or be sure that the evaporator temperature is correct in a direct

expansion system. The CFM should be obtained from a reliable source or measurements should be taken.Call the entering dry bulb and wet bulb temperatures T1DB and T1WB. Call the initial leaving dry bulb andwet bulb temperatures T30DB and T30WB. T30DB/T30WB is the air condition leaving the cooling coil beforeheat pipes are installed. T3DB/T3WB will be used for the air condition leaving the cooling coil and enteringthe reheat heat pipe module with the heat pipes installed.

Next select a precool/reheat T. This is the temperature difference across both the precool and the reheat

heat pipe modules (the T across the reheat heat pipe module will be about the same as the T across theprecool heat pipe module as long as condensation is not taking place during precool). The greater the reheat

T, the lower the SHR (sensible heat ratio) which means that a greater percentage of the cooling effort will be

devoted to latent cooling. Also, as the reheat T increases, the relative humidity of the air entering the supply

duct decreases. Meanwhile, the precool T also increases with increasing reheat T, giving a lowerapproach temperature to the cooling coil so that the air leaving the cooling coil is colder with less moisture

content. Using a psychrometric chart, determine T1DP, the dew point temperature corresponding toT1DB/T1WB.

Calculate

T2DB = T1DB - T

If T2DB < T1DP then there is condensation across the precool heat pipe module and the HeatPipe Technology software must be used. If not, you may proceed with the selection manually.

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DHP-26

Next estimate new values for T3DB and T3WB with heat pipes installed. For chilled water cooling coils,

T3WB T30WB - 0.19 T

T3DB T30DB - 0.19 T

For direct expansion (DX) systems where T30DB/T30WB occurs near the saturation line on thepsychrometric chart,

T3WB T30WB - 0.32 T

T3DB T3WB + (T30DB - T30WB) x [1 (T/20)] forT 20

T3DB T3WB forT > 20

The temperatures leaving the reheat heat pipe module are

T4DB = T3DB + TT4WB = Wet bulb temperature corresponding to T4DB. Draw a line on the psychrometric chart

from T3DB/T3WB to the right to T4DB and read T3WB on the wet bulb scale.

If the leaving temperatures are acceptable, proceed with figuring the size of the heat pipes. Remember toadd in any fan heat to T4DB/T4WB to give the final supply condition.

The required efficiency of the heat pipes is

= T / (T1DB - T3DB)

Measure the fin height, FH, and finned length, FL, of the cooling coil. The fin height is the side of the finnedface area perpendicular to the tubes. If the tubes are horizontal, as they normally are, and the cooling coil isin a vertical plane, the fin height is the vertical dimension of the finned face area. The finned length is theside of the finned face area parallel to the tubes. Calculate the face velocity

V = 144 x CFM / (FH x FL), V is in FPM (feet per minute) and FH and FL are in inches

Refer to Table DHP01. At the calculated face velocity, determine the number of heat pipe rows (precool andreheat) that are necessary to meet the required heat pipe efficiency. Find the static pressure drop across theheat pipes from Table DHP02.

C. New Equipment

Calculate the sensible and latent loads of the space and calculate the sensible heat ratio of the space. Selectthe appropriate equipment. If the SHR (sensible heat ratio) of the space is low (humid climates), moststandard equipment will not be able to meet the latent load without it being oversized.

Dehumidifier heat pipes precool and reheat the air, lowering the SHR of the A/C unit to more closely match

the load. This allows the designer to meet the latent load without using active reheat and oversizing theequipment.

Follow the same procedure as for existing equipment above except that the design values of entering andleaving temperatures and the airflow rate can be used instead of measuring them.

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DHP-27

D. Example

In the proceeding example shown on the psychrometric chart,

Air flow rate: 6,000 CFMFin Height FH: 48 in.Finned Length FL: 67 in.Entering air T1DB/T1WB: 80.0/67.0 FDB/FWBLeaving air (without heat pipes) T30DB/T30WB: 59.4/57.5 FDB/FWBEntering dew point temperature T1DP: 60.4 F

Precool/reheat T: 8.0 F

T2DB = T1DB - T= 80.0 - 8.0= 72.0

T2DB < T1DP so that there is little or no condensation in the precool heat pipe.

T3WB T30WB - (0.32 x T)

57.5 (0.32 x 8) = 57.5 2.56

54.9

T3DB T3WB + (T30DB - T30WB) x [1 (T/20)]

54.9 + { (59.4 57.5) x [1 - (8.0/20)] } = 54.9 + [ 1.9 x (1 0.4) ] = 54.9 + 1.1

56.0

T4DB T3DB + T

56.0 + 8.0

64.0

T4WB 58.0 from psychrometric chart

T / (T1DB - T3DB)

8.0 / (80.0 - 56.0)

0.333

V 144 x 6,000 / (48 x 67)

268.7 FPM

From Table DHP01, a 2-row heat pipe has an effectiveness of 0.365 at 270 FPM. The airside pressure dropin 0.077 in. WG through the precool heat pipe module and 0.077 in. WG through the reheat heat pipemodule.

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DHP-28

Computer Assisted Procedure:

Available from Heat Pipe Technology is software for calculating dehumidifier heat pipe performance. Alsoavailable from most A/C equipment manufacturers is software for calculating the performance of the coolingcoil. If the designer has both the Heat Pipe Technology software and the A/C equipment software, the

programs may be used together to determine performance of the A/C unit with the heat pipes.

First determine the cooling coil entering and leaving dry bulb and wet bulb temperatures without heat pipes,T1DB/T1WB and T30DB/T30WB, and the airflow rate in CFM. Refer to the "Manual Procedure" for adescription of these values. These values will be measured values for existing equipment or design valuesfor new equipment.

Then run the A/C program using T1DB/T1WB and CFM as inputs. The program should giveT30DB/T30WB, the initial leaving dry bulb and wet bulb temperatures without heat pipes. Now turn to theheat pipe performance program. Use T1DB/T1WB as the entering conditions to the precool heat pipemodule and use T30DB/T30WB as initial values for T3DB/T3WB, the condition of the air leaving the coolingcoil and entering the reheat heat pipe module. The heat pipe program will give T2DB/T2WB, the air conditionof the air leaving the precool heat pipe module and entering the cooling coil. Now run the A/C program again

using T2DB/T2WB as the entering conditions. The A/C program will probably give values of T3DB/T3WBthat are different from those used the first time the A/C program was run. Repeat the procedure untilT3DB/T3WB remains the same.

Read from the heat pipe program T4DB/T4WB, the air condition leaving the reheat heat pipe module, and thestatic pressure drops across the precool and reheat modules.

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DHP-29

Table DHP01 HEAT PIPE EFFECTIVENESSNon-condensing only.Copper 1/2 in. OD. tubes, Aluminum fins, 12 fins/in.

Face Velocity (FPM) 1 Row 2 Row 3 Row 4 Row 5 Row 6 Row200 0.249 0.399 0.499 0.571 0.624 0.666

210 0.245 0.399 0.494 0.565 0.619 0.661

220 0.241 0.389 0.488 0.560 0.614 0.656

230 0.237 0.383 0.483 0.554 0.608 0.651

240 0.233 0.378 0.477 0.549 0.603 0.646

250 0.230 0.374 0.472 0.544 0.599 0.641

260 0.226 0.369 0.467 0.539 0.594 0.637

270 0.223 0.365 0.463 0.534 0.589 0.633

280 0.220 .0360 0.458 0.530 0.585 0.628

290 0.217 0.356 0.453 0.525 0.580 0.624

300 0.214 0.352 0.449 0.521 0.576 0.620

310 0.211 0.348 0.445 0.517 0.572 0.616

320 0.208 0.345 0.441 0.513 0.568 0.612

330 0.205 0.341 0.437 0.509 0.564 0.608

340 0.203 0.337 0.433 0.505 0.560 0.604

350 0.200 0.334 0.429 0.501 0.556 0.601

360 0.198 0.331 0.426 0.497 0.553 0.597

370 0196 0.327 0.422 0.493 0.549 0.593

380 0.193 0.324 0.419 0.490 0.545 0.590

390 0.191 0.321 0.415 0.486 0.542 0.587

400 0.189 0.318 0.412 0.483 0.538 0.583

410 0.187 0.315 0.409 0.479 0.535 0.580

420 0.185 0.313 0.406 0.476 0.532 0.577

430 0.183 0.310 0.465 0.473 0.529 0.574

440 0.181 0.307 0.399 0.470 0.525 0.571

450 0.179 0.304 0.396 0.467 0.522 0.567

460 0.178 0.302 0.393 0.464 0.519 0.565

470 0.176 0.299 0.390 0.460 0.516 0.562

480 0.174 0.297 0.388 0.458 0.513 0.559

490 0.173 0.294 0.385 0.455 0.511 0.556

5000.171 0.292 0.382 0.452 0.508 0.553

510 0.169 0.290 0.380 0.449 0.505 0.550

520 0.168 0.287 0.377 0.447 0.502 0.548

530 0.167 0.285 0.375 0.444 0.500 0.545

540 0.165 0.283 0.372 0.441 0.497 0.542

550 0.163 0.281 0.370 0.439 0.494 0.540

Note: Contact factory for higher air face velocities.

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DHP-30

Table DHP02 HEAT PIPE STATIC PRESSURE DROPNon-condensing only.Copper 1/2 in. OD. tubes, Aluminum fins, 12 fins/in.

Face Velocity (FPM) 1 Row 2 Row 3 Row 4 Row 5 Row 6 Row

200 0.026 0.046 0.067 0.088 0.109 0.130

210 0.028 0.050 0.073 0.096 0.118 0.141

220 0.030 0.054 0.079 0.103 0.128 0.152

230 0.032 0.059 0.085 0.077 0.138 0.266

240 0.035 0.063 0.091 0.120 0.148 0.176

250 0.037 0.068 0.098 0.128 0.158 0.189

260 0.040 0.072 0.144 0.137 0.169 0.202

270 0.042 0.077 0.111 0.146 0.180 0.215

280 0.045 0.082 0.118 0.155 0.192 0.228

290 0.048 0.087 0.125 0.164 0.203 0.242

300 0.051 0.092 0.133 0.174 0.215 0.256

310 0.053 0.097 0.140 0.184 0.227 0.271

320 0.056 0.102 0.148 0.194 0.240 0.286

330 0.059 0.108 0.156 0.204 0.138 0.301

340 0.062 0.113 0.164 0.215 0.265 0.316

350 0.065 0.119 0.172 0.225 0.279 0.332

360 0.069 0.124 0.180 0.236 0.292 0.348

370 0.072 0.113 0.189 0.247 0.306 0.364

380 0.075 0.136 0.198 0.259 0.320 0.381

390 0.078 0.142 0.206 0.270 0.334 0.398

400 0.082 0.149 0.215 0.282 0.349 0.415410 0.085 0.155 0.224 0.294 0.363 0.433

420 0.089 0.161 0.234 0.306 0.378 0.451

430 0.092 0.168 0.243 0.318 0.394 0.469

440 0.096 0.174 0.253 0.331 0.409 0.488

450 0.100 0.181 0.262 0.344 0.425 0.506

460 0.103 0.188 0.272 0.357 0.441 0.525

470 0.107 0.195 0.282 0.370 0.457 0.545

480 0.111 0.202 0.292 0.383 0.474 0.544

490 0.115 0.209 0.302 0.396 0.490 0.584

500 0.119 0.216 0.313 0.410 0.507 0.604

510 0.123 0.223 0.324 0.424 0.524 0.625

520 0.127 0.231 0.334 0.438 0.542 0.645

530 0.131 0.238 0.345 0.452 0.559 0.666

540 0.135 0.246 0.356 0.467 0.577 0.688

550 0.140 0.254 0.367 0.481 0.595 0.709

Note: Contact factory for higher air face velocities.

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DHP-31

RELATIVE HUMIDITY DATA

Amounts of Moisture Contained in Air

Air Temp. Pounds of Water Contained in 1000 Cubic Feet of Air

at Relative Humidity

90% 80% 70% 60% 50% 40% 30%

100F 2.56 2.28 2.00 1.71 1.43 1.14 .86

95F 2.22 1.98 1.73 1.48 1.23 .99 .74

90F 1.92 1.71 1.49 1.28 1.07 .85 .64

85F 1.65 1.47 1.29 1.10 .92 .74 .55

80F 1.42 1.26 1.10 .95 .79 .63 .47

75F 1.21 1.08 .95 .81 .68 .54 .41

70F 1.03 .92 .80 .69 .57 .46 --

65F .88 .78 .68 .59 .49 -- --

60F .75 .66 .58 .50 .41 -- --

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DHP-32

DATA GATHERING WORKSHEET I


IdentificationProject: _____________________________________________________________________________Equipment No.: ______________________________________________________________________Location of Job: ______________________________________________________________________

A) Air Entering Cooling Coil, Return/Outside AirTemperature: ________ F DB Relative Humidity: _________ %

B) Air HandlerManufacturer: ________________________ Model No.: ________________________Nominal Capacity: _________________ Ton Supply Air Temperature: _________ Fdb/ FwbMotor Power: ___________ hp Nameplate Amps. _________ Actual Amps: ________Total Static Pressure: ________ RPM: _______________________________________

C) Air Flow

Return Air Flow: ________ CFM Fresh Air Flow: ________ CFM Total Air Flow: _________ CFM

D) Cooling Coil Data**Finned Height: ____________________ Finned Length: _______________________Direct Expansion: __________________

Chilled Water: ____________________ Chilled Water Temperature In: _____F Out: _____F

E) ReheatElectric:__________ kW Hot Water: _______ BtuH Other: ___________Reheat _____ Yes _____ No

**Use the drawing on the following page to supply the data for cooling coil dimensions.

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DHP-33

DATA GATHERING WORKSHEET II


Factory or Field Installed

VERTICAL

Dimensions

D

E

F

Front

A

B

C

D

E

F

Supply Air

ReturnAir

Filter

Cooling

Coil

Blower

Side

A C

B

Dimensions

D

E

F

Front

A

B

C

D

E

F

ReturnAir

Filter

CoolingCoil

Blower

Side

A C

B

Supply

Air

HORIZONTAL

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DHP-34

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DHP-35

Installation List

Example of Commercial InstallationsWrap-Arou nd Dehumidi f ier Heat PipesTM(DHP)

State City LocationAlabama Dothan Sony Corporation

Birmingham Redstone Arsenal

Mobile Gross Anatomy Lab

Warring Elementary

Arkansas North Little Rock Baptist Memorial Medical

Bahamas Nassau Soloman Brothers

Connecticut Oxford Peter Paul Candies

Bloomfield Hamilton Standard MeteorologyDelaware Wilmington Dupont Auto

Dupont Building

Florida Bradenton Manatee Community College

Brooksville Spartan Electronics

Cape Canaveral NASA, Kennedy Space Center

Crestview Crestview High School

Davies Nova University

Daytona Beach Embry-Riddle Aeronautical University

Ft. Lauderdale Broward County Courthouse

Gainesville North Florida Regional Medical Center

Santa Fe Community College

University of Florida

Green Cove Springs Clay County School Board

Jacksonville Central Florida Community College

Marriott Hotel

Lake City Lake City Community College

Largo Architectural Design Center

Melbourne Brevard Co. Facility Maintenance

Miami Teletronics Pacing Systems

University of Miami

Orlando Disney World

Pensacola Bay Medical Center

St. Petersburg Bay Front CenterSaccino & Sons Formal Wear

Sarasota Ringling School of Art & Design

Stuart Martin County Schools

Tallahassee Governor's Residence

W.T. Moore Elementary School

Tampa American Home Patient Center

Microview Microfiche Film Processing

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DHP-36

State City Location

Florida Tampa Tampa Brass and Aluminum

Venice Sarasota County Courthouse

West Palm Beach Palm Beach Atlantic CollegeGeorgia Albany Cooper Tires

Atlanta Marriott NW Windy Hill

Conyer Edwards Food Store

Guam Agana Park Beach Hotel

Barrigada Naval Station

Hawaii HonoluluMoanalua Medical Center(at Kaiser-Permanente Hospital)

St. Francis Medical

Illinois Chicago Dominicks Store #122

Elk Grove Village Dominicks Store #129

Indiana Indianapolis Marsh Supermarkets

Mishawaka Martin Supermarkets

Indianapolis Rushville High School

Iowa Davenport Rock Island High School

Louisiana Boyce Northwood High School

New Orleans Keesler AFB Locker

Metaire La Rose Office Park

Maryland Capital Heights Asbury Methodist Home

Gaitherburg Asbury Methodist Nursing Home

Owing Mills USA-APG

Massachusetts Boston MIT Lincoln Lab

Michigan Ann Arbor Gelman Science

Farmington Hills Holly High SchoolMinnesota Sauk Rapids Coborn's Foley Project

Mississippi Biloxi Kentucky Fried Chicken

Gulfport Memorial Hospital at Gulfport

Jackson Barnett Building

Missouri Flat River USDA, Federal Center

Kansas City Midwest Research

New Jersey Denville St. Clare's Hospital

Linden Yokoha Tire Plant

Pinebrook Masonic Home

New York Astoria Callico Cottage

Brooklyn Avaho IndustryNorth Carolina Greensboro Animal Research Facility

Rocky Mountain Greenville Art Museum

Ohio Canton Finast Supermarkets

Cincinnati Cedar Village

Columbus Defense Distribution Reg. E

Pennsylvania Giant Supermarkets

Bristol NJEDA Project

Philadelphia Flexible Circuits

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DHP-37

State City Location

Puerto Rico Caguas Olazabel

San Juan Warner Lambert PR

South Carolina Columbia Criminal Justice Driving Range

Greenville MUSC Substance Abuse Center

Lexington Lexington County Middle School

Tennessee Farragut St. John Newman

Knoxville University of Tennessee Medical Center

Memphis Obion County Jail

University of Memphis, Clement Hall

Texas Austin K-Tech, Phase II

Dallas Humana City Hospital

Houston Youn's Residence

Pearland MD Adderson Hospital

Virginia Amherst Washington University, Brown Hall

Norfolk United States NavyOthers 40+ Locations across U.S Sam's Wholesale Club

Partial Listing of Overseas Installation

Dehum idif ier Heat PipesTM

State City LocationCuba Air Base School

Irondale Guantanamo Bay

Dominican Republic Santo Domingo Central Bank

Korea Gujae Shin Sung Shipyard

Panama Panama City Executive Hotel Panama

Puerto Rico San Juan Contemporary Museum

Hilton San Juan

Johnson & Johnson Pharmaceutical Plant

U.S. Navy Base

Taiwan Taichung Panmax Corporation

Tainan Chi-May Hospital

Taipei Police College Library

Thailand Bangkok Alphatec Co.

Philips Semiconductors (Thailand) Co., Ltd.

Sony Semiconductors (Thailand) Co., Ltd.

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DHP-38

Dehumidifier Heat Pipe Monoflat & Wrap Around Series Check List

Company: ________________________________

Phone: (____) ________ Fax: (___) __________

Job Name: _______________________________

Model # : ___________ Serial # : ____________

Test performed by: ______________ Date: ______

Test Cooling Heating

Temp.

F DB

Temp.

F WB

Press.in. H2O

CFMTemp. Temp.

F WB

Press.in. H2O

CFM

Entering Air @1Entering Air @2

Leaving Air @3

Leaving Air @4

Outside Air?Yes.No. _______ F DB _______ F WB _______ CFM or _______ %Entering/Leaving Air Duct Sizes Ent.: ______ "Depth ______ "W Leav.: _____ "Depth _____ "W

Blower Speed: ______ hp: ______ _________ Volt ________ Amps ________ Volt ________ Amps

AirS

ide

Monoflat orWrap Around? DIM. Ent.: ________ "H ________ "W Leav.: _______ "H _______ "W

SystemDirect Expansion (DX) orChilled Water (CW) System?

System Brand ___________ Model ____________ Nominal Capacity ____________ EER: ___________

Hi Discharge Pressure/ Sat. Temp. __________ Psig __________ F _________ Psig _________ F

Liquid Line Temp./Sight Glass __________F SG Clear? _________F SG Clear?Low Suction Pressure/Sat. Temp. __________ Psig __________ F _________ Psig _________ F

Suction Line Temp. @ coil outlet _____________ F _____________ F

Suction Superheat _____________ F _____________ F

Liquid/Suction Line Length/Size Liquid: _______ ft. _______ "OD Suction: ______ ft. ______ "OD

DX

Compressor ___ Volt/Amps @Outdoor F _________ Amp @ _________ F ________ Amp @ ________ F

CW Water GPM/Temperature In & Out GPM: _______ Fin _______ Fout GPM: ______ Fin ______ Fout

REHEAT:Elec.WaterOther? kW Btu kW Btu

Important

Condensate flow in 15 min. __________ .

Note: To perform Condensate Flow test, run unit for 15 min., then capture condensate for 15 min. in a graduatedcontainer. For Chilled Water systems, make sure to fully open chilled water modulating valve before performingtest.

1 2

4 3 3

Monoflat

1

Wrap-Around

2

4

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Five-Year Limited Warranty

Subject to the following conditions, Heat Pipe Technology, Inc. (HPT), warrants this product to be free from defects in material andworkmanship for a period of FIVE YEARS from the date of installation. Warranty automatically begins twelve (12) months from ship dateshould installation not occur during this period. This warranty is in lieu of all other warrants not expressly set forth herein, whether expressed orimplied by operation of law or otherwise. In the event this product fails under normal use and service within the applicable period, HPT willcorrect, repair or, at its sole discretion, replace the defective product or refund the purchase price of products which are returned freight prepaidto HPT for inspection, when accompanied by proof of purchase and written claims of defect, and which upon inspection by HPT, do complywith the terms of this warranty.

This warranty applies to the first retail buyer and extends to any subsequent owners of the systems.

The cost of replacement parts or components shall be determined by the price schedule in effect at the time of submission of warranty claim.

Repair or replacement parts will be furnished F.O.B. factory in all cases.

If HPT elects to replace or provide a refund, the defective product must be returned to HPT free and clear of liens or other encumbrances.

Limitations on Liability

This warranty does not cover and no warranty is made with r espect to:

A. Failures not reported to HPT within the period specified above;B. Failures or damage due to misapplication, misuse, abuse, improper storage or handling, abnormal conditions of temperature, water, dirt,

corrosive substances or other contaminants;C. Products which have been repaired with parts or materials not furnished or approved by HPT or by its authorized dealers or

representatives, or products which have been in any way tampered with or altered;D. Products damaged in shipment or storage or otherwise without fault of HPT;E. Normal maintenance as outlined in the installation and servicing instructions or owners manual including coil cleaning, filter cleaning and

periodic flushing of systems;F. Damage or repairs required as a consequence of faulty installation or application by others;G. Damage or repairs required as a consequence of any misapplication, abuse, improper servicing, unauthorized alteration or improper

operation;H. Damage as a result of floods, winds, fires, lightning, accidents, corrosive atmosphere or other conditions beyond the control of HPT;I. Damage resulting from freezing of domestic water or condensate, inadequate or interrupted water supply, use of corrosive water, fouling

or restriction of the water circuit by foreign material or like causes;J. Damage resulting from operation with an inadequate supply of air or water;K. Dampers or o ther mechanical options.

HPT total responsibility for any claims, damages, losses or liabilities related to the product covered hereunder shall not exceed the purchaseprice of such product. In no event shall HPT be liable for any special, indirect, incidental or consequential damages of any character, including

but not limited to loss of use of productive facilities or equipment, lost profits, property damage, transportation, installation or removal, lostproduction, or personal injury whether suffered by Purchaser or any third party. HPT disclaims all liability for any and all costs, claims,demands, charges, expenses or other damages, either direct or indirect, incident to personal injury or property damage arising out of any causeof action based on strict liability.

Some states do not allow the exclusion or limitation of incidental or consequential damages or limitations on how long an implied warrantylasts, so the exclusion or limitation above of consequential damages or the limitation of time above on implied warranties may not apply to you.

This warranty gives you specific legal rights and you may have other rights which may vary from state to state.

DHP-39

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Warranty Registration

To insure your warranty protection, please fill in the Warranty Registration Form and mail or fax it to:

Heat Pipe Technology, Inc.

4340 North East 49th

Avenue, Gainesville, Florida 32609Fax: (352) 367-1688

WARRANY REGISTRATION FORM

Customer Name:

Customer Address:

Phone: ( ) - Fax: ( ) -

Please check one: Homeowner Dealer

Serial No: Model No:

Type of Product:

Date of Installation: Dealer/Installer:

Name & Address of Dealer/Company You Purchased from

Name:

Address:

Customer Signature:

dhp.pdf

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