AHRI IWH-TS-1-2003 PERFORMANCE OF INDIRECT-FIRED WATER HEATERS - TESTING STANDARD.pdf

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1、Indirect-Fired Water Heater Testing Standard IWH-TS-1 March 2003 GAMA TESTING STANDARD Method to Determine PERFORMANCE OF INDIRECT-FIRED WATER HEATERS March 2003 Edition Sponsored by Gas Appliance Manufacturers Association, Inc. Arlington, Virginia 22201 Telephone: (703) 525-7060 Program Administrat

2、or Gas Appliance Manufacturers Association, Inc. Hydronics Institute Division Rating Program Berkeley Heights, New Jersey 07922-0218 Telephone: (908) 464-8200 024 Indirect-Fired Water Heater Testing Standard IWH-TS-1 - March 2003 2 TESTING STANDARD Method to Determine Performance of Indirect-Fired W

3、ater Heaters TABLE OF CONTENTS Section 1 Purpose. 1 Section 2 Scope 1 Section 3 Definitions 1 Section 4 Instruments 3 Section 5 Apparatus 3 Section 6 Test Condition . 5 Section 7 Test Procedure 9 Section 8 Data To Be Recorded 12 Section 9 Calculations. 12 Section 10 Test Report 15 FIGURES 1 Example

4、Of Test Setup . 6 2 Example Of Test Setup When Mixing Valve Is Used 7 FORMS IWH-TS-1 Indirect-Fired Water Heater Volume Log. 17 IWH-ST-1 Indirect-Fired Water Heater Standby Test Log 18 IWH-CD-1 Indirect-Fired Water Heater Continuous Draw Test 19 IWH-FD-1 Indirect Water Heater First Draw Test. 20 IWH

5、-R-1 Indirect-Fired Water Heater Report Sheet. 21 TABLES 3 Density Of Water. 22 Exibit A Least Square Method For A Straight Line Through A Series Of Points 23 Indirect-Fired Water Heater Testing Standard IWH-TS-1 - March 2003 3 TESTING STANDARD Method to Determine PERFORMANCE OF INDIRECT-FIRED WATER

6、 HEATERS March 2003 Edition 1.0 PURPOSE To establish a method of test to determine the performance of Indirect-Fired Water Heaters; both Indirect-Fired Storage Waters Heaters and Indirect-Fired Instantaneous Water Heaters. 2.0 SCOPE 2.1 This test method is intended to apply to Indirect-Fired Water H

7、eaters designed for installation with a hot water boiler or some other external source of heated water. 2.2 This standard is limited to Indirect-Fired Water Heaters having a total volume (potable plus heat source) of 120 gallons or less. 2.3 This standard does not apply to direct-fired instantaneous

8、 or storage water heaters, direct fired instantaneous water heaters, tankless water heaters, or heat pump water heaters. 3.0 DEFINITIONS COMBINATION SPACE HEATING AND WATER HEATING APPLIANCE - A unit designed to provide space heating and potable water heating from a single primary energy source. HOT

9、 WATER STORAGE TANK - A tank used to store heated, potable water. INDIRECT-FIRED STORAGE WATER HEATER - A water heater consisting of a potable hot water storage tank equipped with an internal or external heat exchanger used to transfer heat to the stored potable water from an external source. INDIRE

10、CT-FIRED INSTANTANEOUS WATER HEATER - A water heater consisting of a tank which contains hot water from an external source and a heat exchanger used to transfer heat from this stored water to the potable water. TANKLESS WATER HEATER - A heat exchanger for indirect heating of domestic water, designed

11、 to be used without a Indirect-Fired Water Heater Testing Standard IWH-TS-1 - March 2003 4 domestic water storage tank. It may be attached directly to the boiler, or installed external to the boiler and connected by piping. THERMOSTAT, TANK - A device which senses changes in stored water temperature

12、, and controls by means of separate components, the flow of energy to maintain selected temperatures. 3.1 NOMENCLATURE cpSpecific heat of water, Btu per pound F DR Mean tank water temperature decay rate during standby test, F per hour DRuUncorrected mean tank water temperature decay rate during stan

13、dby test, F per hour Q Standby heat loss from the Indirect-Fired Water Heater tank in Btu/hr QhHeat exchanger heat input for indirect-fired storage water heater, Btu per hour TaMeasured ambient air temperature, F TcCold water supply temperature, F TiMeasured potable water inlet temperature, F Ti,avg

14、Average potable water inlet temperature, F TihInlet heat source water temperature to the Indirect-Fired Water Heater, F Tih,avgAverage inlet heat source water temperature to the Indirect-Fired Water Heater, F ToMeasured potable water outlet temperature, F To,avgAverage potable water outlet temperatu

15、re, F TohOutlet water temperature from Indirect-Fired Water Heater to heat source, F Toh,avgAverage outlet water temperature from Indirect-Fired Water Heater to heat source, F To(max)Maximum potable water outlet temperature, draw test, F TsMean tank temperature, F V Potable water volume for indirect

16、-fired storage water heater, gallons VcVolume of potable water drawn during continuous draw test, gallons per 30 minutes VcdContinuous draw rating, gallons per hour VdVolume of potable water drawn duing the first draw test, gallons V(end)Volume reading of potable water meter at end of first draw tes

17、t, gallons VfFirst hour rating, gallons per hour VhHeat source water volume for indirect-fired storage water heater, gallons Vt Initial volume reading of potable meter reading at begining of first draw test, gal w Water flow rate (potable) in Indirect-Fired Water Heater, gallons per minute whWater f

18、low rate (heat source) for Indirect-Fired Water Heater, gallons per minute wh,avgAverage water flow rate (heat source) for Indirect-Fired Water Heater, gallons per minute WcTotal weight of potable water drawn during continuous draw test, pounds per 30 minutes WdTotal weight of potable water drawn du

19、ring first draw test, pounds WpWeight of tank when filled with potable water, pounds WphWeight of tank when filled with potable and heat source water, pounds WtDry weight of tank, pounds WT(end)Weight of weigh tank and potable water at end of first draw test, pounds Indirect-Fired Water Heater Testi

20、ng Standard IWH-TS-1 - March 2003 5 WTtInitial weight of weigh tank at beginning of first draw test, pounds Density of water, pounds per gallon (see Table 3) 4.0 INSTRUMENTS 4.1 GENERAL All instruments shall be in working order and be calibrated periodically. Records of periodic calibration shall be

21、 kept and they shall contain, at a minimum, the date of calibration, method of calibration, and reference standard used. 4.2 TEMPERATURE 4.2.1 THERMOMETERS Shall have an error no greater than 1F. 4.2.2 THERMOCOUPLES Unless otherwise specified herein, thermocouples and their read out instrumentation

22、shall have an error no greater than 0.2F for all readings. Thermocouples shall be the bead type having a wire size no greater than No. 24 American Wire Gauge (AWG). Water temperatures thermocouples shall be the immersion type. The meter for reading the temperature shall have 0.1F graduations 4.3 PRE

23、SSURE Water pressure measuring instruments shall be calibrated so that the error is not greater than 1 pound per square inch. 4 .4 WEIGHT OR VOLUME The error associated with the measuring instruments shall not exceed 0.5 percent of the quantity measured. 4.5 TIME The error associated with timing ins

24、truments shall not exceed 0.5 seconds per hour. 4.6 WATER FLOW RATE A flow meter, if used, shall be calibrated so that the error is no greater than 0.5 percent of the hourly rate. 5.0 APPARATUS The apparatus described below is used in conjunction with Indirect-Fired Water Heaters during the testing.

25、 5.1 PIPING See Figure 1 for a conceptual piping arrangement. Provisions shall be made to assure constant supply water temperature and pressure to the unit. Figure 2 contains a conceptual piping arrangement for an Indirect-Fired Water Heater that uses a mixing valve as determined by 5.5. 5.2 WATER F

26、LOW MEASUREMENT Provide appropriate weigh tanks and scales, or calibrated meters, to measure water flow. 5.3 ROOM TEMPERATURE Indirect-Fired Water Heater Testing Standard IWH-TS-1 - March 2003 6 Install a thermocouple to measure the ambient temperature with junction shielded against direct radiation

27、 from any heat source and positioned at the vertical midpoint of the unit at a perpendicular distance of approximately 24 inches from the surface of the tank jacket. 5.4 THERMOCOUPLE INSTALLATION FOR WATER TEMPERATURES 5.4.1 THERMOCOUPLE INSTALLATION Install six or more thermocouples inside the tank

28、. The thermocouples may be installed in the tank either through (1) the opening for the anode rod, (2) the relief valve opening, (3) the hot water outlet, or (4) other suitable location. Position each thermocouple measuring junction along a vertical line at the level of the center horizontal plane o

29、f each non-overlapping sections of approximately equal volume, from the top to the bottom of the tank; such that each thermocouple is surrounded by water and as far as possible from any heat input device, anodic protective device, tank wall, or other irregularity. The anodic protective device may be

30、 removed in order to install the thermocouples and all testing may be carried out with the device removed. If the thermocouples are installed through the hot water outlet, a nonmetallic fitting assembly shall be installed such that the outlet piping is installed as close as possible to its original

31、location. If the hot water outlet includes a heat trap, the heat trap shall be reinstalled on top of the tee fitting. If the thermocouples are installed through the relief valve, a metallic fitting assembly shall be used outside the tank and installed as close as possible to the original location. T

32、he added exposed metal tubing shall be insulated, except the relief valve, with a thermal insulation having a value of at least R = 4F h ft2/Btu. Install thermocouples in both the cold water inlet pipe and the hot water outlet pipe, not more than 24 inches from the connections to the water heater; o

33、r, where those connections are inaccessible, at the closest accessible point to those connections. Install thermocouples in the pipe connecting the heat source to the heat exchanger and in the pipe returning the water to the heat source within 24 inches of the connection to the heat exchanger. Locat

34、e the thermocouples downstream of two elbows, or a turbulator, to assure good mixing. 5.4.2 MEAN TANK TEMPERATURE MEASUREMENT Mean tank temperature of the water in the water heater tank, wherever specified, shall be the mean of the temperatures determined by using the thermocouples installed in the

35、tank as specified in 5.4.1. 5.5 MIXING VALVES Testing an Indirect-Fired Water Heater utilizing a mixing valve is permitted, as long as the mixing valve is supplied by the manufacturer as standard equipment. In such cases, the mixing valve used for testing shall be the same valve provided by the manu

36、facturer, and shall be installed in accordance with the manufacturers instructions. The outlet water temperature, TO, shall be taken using a thermocouple in a heat trap connected to the “mixed“ outlet of the valve. If a water meter is used, it shall be installed upstream of the cold water connection

37、 to the mixing valve so that the total water volume drawn through both the hot and cold mixing valve connections is measured (Figure 2). 5.6 HEAT SOURCE A laboratory source of heated water shall be provided, with sufficient capacity to adequately supply the largest unit to be tested. Indirect-Fired

38、Water Heater Testing Standard IWH-TS-1 - March 2003 7 6.0 TEST CONDITIONS Indirect-Fired Storage Water Heaters and Indirect-Fired Instantaneous Water Heaters shall be equipped with the apparatus described in Section 5, and the instrumentation described in Section 4, and shall be set up for recording

39、 data. Refer to Figure 1 when equipping the test unit with the apparatus and instrumentation. The heaters shall be adjusted to the test requirements or conditions described in Sections 6 and 7. Indirect-Fired Water Heater Testing Standard IWH-TS-1 - March 2003 8 Indirect-Fired Water Heater Testing S

40、tandard IWH-TS-1 - March 2003 9 Indirect-Fired Water Heater Testing Standard IWH-TS-1 - March 2003 10 6.1 INSTALLATION 6.1.1 INSTALLATION Install the water heater according to the manufacturers installation instructions on a inch thick plywood platform elevated approximately 4 inches off the floor b

41、y three 2 X 4 inch runners. An appropriately rated pressure and temperature relief valve shall be installed in the location specified by the manufacturer. 6.1.2 HEAT SOURCE PIPING The connecting pipe between the thermocouple and the Indirect-Fired Water Heater shall be metal pipe up to the thermocou

42、ple and the balance of the piping may be as specified by the testing laboratory (see Figure 1). 6.1.3 POTABLE WATER PIPING The piping connecting the potable water inlet and outlet to the Indirect-Fired Water Heater shall be of the same size as the tank connections and each shall have a heat trap loo

43、p located at the closest accessible point to these connections. Provide a pressure gauge, a diaphragm type expansion tank, and a check valve in the water supply line. The piping between the potable water inlet and the inlet water thermocouple shall be threaded metal pipe and the balance of the pipin

44、g may be as specified by the lab (see Figure 1). 6.2 AIR AND WATER 6.2.1 WATER SUPPLY 6.2.1.1 POTABLE WATER During all of the draw tests, maintain the potable water supply at (Tc= 58F 2F) and at a gauge pressure of between 40 psig and the maximum pressure specified by the manufacturer for the unit u

45、nder test. If the water supply pressure varies outside of these limits during testing, the heater shall be isolated by use of a shut-off valve in the supply line with an expansion tank installed in the supply line downstream of the shut-off valve. There shall be no shut-off means between the expansi

46、on tank and the water heater inlet. 6.2.1.2 HEAT SOURCE WATER SUPPLY During all of the draw tests, the water supplied to the water heaters heat exchanger inlet, T, shall be 180F 2.5F. 6.2.2 WATER FLOW RATES Maintain the required potable water flow rate, w, within 0.25 gpm at all times during the tes

47、t (see 7.3.2). Maintain the heat source water flow rate, wh, within 0.25 gpm. 6.2.3 AIR TEMPERATURE Maintain the ambient air temperature, Ta, of the test room, as measured according to Section 5.3., as follows: Standby Test 70F 5F Continuous Draw and First Draw Tests 75F 10F Indirect-Fired Water Hea

48、ter Testing Standard IWH-TS-1 - March 2003 11 7.0 TEST PROCEDURE At the manufacturers discretion, an Indirect-Fired Water Heater may be operated prior to the start of the tests. This shall be accomplished by maintaining the mean potable water tank temperature,Ts, for a period of at least 24 hours, a

49、t the initial starting conditions specified under 7.2. 7.1 WATER VOLUME DETERMINATION Install valves and any other fittings on the Indirect-Fired Water Heater that will be necessary to fill its potable and heat source portions with water. Obtain the empty weight of the Indirect-Fired Water Heater, Wtin pounds with these fittings installed. Fill only the potable water portion of the Indirect-Fired Water Heater with water, ensuring that all air is removed. Record the temperature, Tc, of the water used. Obtain the weight of the I