1、. . - . . -).I- . . . .- ASHRAE 95-198: (Reaffirmation of 95-19E with minor editorial revision: - E Methods of Testing TO DETERMINE THE THERMAL PERFORMANCE O SOLAR DOMESTIC WATER HEATING SYSTEMS Approved by ASHRAE Standards Committee April 18,1986 and ap proved by the Board of Directors July 2, 1987
2、. ASHRAE standards are updated on a five-year cycle; the date follow ing the Sfandard number is the year of approval. The latest copie. may be purchased from the ASHRAE Publications Sales Depart ment, 1791 Tullie Circle, NE, Atlanta, GA 30329. 0 1988 AMERICAN SOCIETY OF HEATING, REFRIGERATING AND AI
3、R-CONDITIONING ENGINEERS, INC. 1791 Tullie Circle, NE Atlanta, GA 30329 . ,- . . I_. ! .- . _. . . . ,. .- . - _ .: - . ,. ASHRAE STANDARDS COMMITTEE 1979-80 Ross F. Meriwether, Chairman Jordan L. Helman, Vice Chairman William L. Beard, Jr. Samuel F. Ciriclllo Robert E. Cook Richard J. Denny Earl J.
4、 Gmoser Dr. Victor Goldschmidt David L. Grumman Gerard lacouue Dr. Preston McNall, Jr. Dr. Stanley A. Murnma Neil R. Patterson Joseph A. Pletsch Jack E. Tumilty Henry C. Waechter Arthur E. Wheeler Clinton W. Phillips, BOD CO Emil E. Friberg, BOD Exo Charles T. Zegers, Manager, Standards SPECIAL NOTE
5、 This National Voluntary Consensus Standard was developed under the auspices of the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE). Con- sensus is defined as “substantial agreement reached by concerned interests according to the judgment of a duly appointed author
6、ity, after a concerted attempt at resolving objections. Con. sensus implies much more than the concept of a simple majority but not necessarily unanimi- ty.“ This definition is according to the American. National Standards Institute (ANSI) of which ASHRAE is a member. ASHRAE obtains consensus throug
7、h participation of its national and international members, associated societies and public review. ASHRAE Standards are prepared by a Project Committee appointed specifically for the pur. pose of writing the Standard. The Project Committee Chairman and ViceChairman must be members of ASHRAE; while o
8、ther members may or may not be members, all must be tech- nically qualified in the subject area of the Standard. Every effort Is made to balance the con- cerned interests on all Project Committees. The Manager of Standards of ASHRAE should be contacted for: a. interpretation of the contents of this
9、Standard. b. participation in the next review of the Standard. c. offering constructive criticism for improving the Standard. d. permission to reprint portions of the Standard. ASHRAE INDUSTRIAL ADVERTISING POLICY ON STANDARDS ASHRAE Standards are established to assist industry and the public by off
10、ering a uniform method of testing for rating purposes, by suggesting safe practices in designing and installing equipment, by providing proper definitions of this equipment and by pro- viding other information which may serve to guide the industry. The creation of ASHRAE Standards is determined by t
11、he need for them, and conformance to them is completely voluntary. In referring to this standard and in marking of equipment and in advertising, no claim shall be made, either stated or implied, that the product has been approved by ASHRAE. The following form of statement should be used: A represent
12、ative product sample of the model, has been tested in accordance with ASHRAE STANDARD 90A-80 - ASHRAE 75 87 W 0759650 OOIJIIIJO 7 = CONTENTS SEMIONS PAGE FOREWORD 1 NOMENCLATURE 2 1. Purpose 3 2. Scope 3 3. Definitions 3 4. Classlficatioans 4 5. Requirements . 5 6. Insfrumentation,. . 5 7. Appartus.
13、 . 8 8. Testprocedures 11 9. Data to be Recorded and Test Report . .13 10. References 13 APPENDIXA 16 APPENDIXB 16 APPENDIXC 17 APPENDIX D .21 APPENDIX E .21 This Foreword is not part of this Standard but is included for information purposes only. . FOREWORD This Standard falls under the Standards C
14、ommittee classification of a standard method of measurement or test. It was prepared by Standards Project Committee 95P, formed in February 1977, and it was approved for publica- tion by the Board of Directors on July 2, 1981. ANSI ap- proved it as an American National Standard on December 17, 1981.
15、 The 1981 Standard was recommended for reaffirmation . . with minor editorial changes by the Standards Committee on April 18,1986. Since the ASHRAE Journal intent-to- reaffirm notice elicited no negative comments, the Board of Directors approved the reaffirmation with minor editorial changes on July
16、 2, 1987. Although the performance of some solar domestic water heating systems can be approximately predicted based on the thermal characteristics of their collector array and storage tanks, it is also affected by the interconnecting pip- ing, control equipment, and interactions between the com- po
17、nents. Consequently, a standard test is outlined for the complete system. It became apparent early in the deliberations of the Com- mittee that testing a completely assembled system with the collector array irradiated was only feasible using a solar simulator. Since such simulators are not yet widel
18、y avail- able, an alternate method has been allowed. Under the alternate method, the collector is first tested separately in accordance with ASHRAE Standard 93-1986. Using these data, the thermal output of the collector array in the solar domestic hot water system is calculated for test conditions a
19、nd input to th? system by using a combination of the non- irradiated collector array and a conventional energy source in the test loop. This Standard specifies the method of testing the solar domestic hot water system but does not specify the test con- ditions to be used for obtaining a standard rat
20、ing. This is normally done in a rating standard which should be developed at a later time by a separate organization such as an industry association. The Committee remained concerned throughout its deliberations about the potentially large costs for conduc- ting the tests. It is hoped that research
21、completedin the near future will indicate how the tests can be shortened and/or replaced by calculations. ASHRAE STANDARD 95-1987 7 - .- 2 I 2 ASHRAE 95 87 = 0757b50 001LL03 7 = NOMENCLATURE = collector module aperture area, m2 (ft2) = intercept of the collector efficiency curve deter- mined in acco
22、rdance with ASHRAE Standard 93-1986, dimensionless = slope of the collector efficiency curve deter- mined in accordance with ASHRAE Standard 93-1986, W/(m2 OC) Btu/(hr ft2 OF) = gross collector area, m2 (ft2) = specific heat of the transfer fluid used in the collector during the ASHRAE Standard 93-1
23、986 tests, kJ/(kg 0 OC) Btu/(lb OF) = specific heat of the transfer fluid used in the collector during the solar hot water system test, = specific heat of water, kJ/(kg OC) Btu/ = nozzle throat diameter, m (ft) = fractional energy savings, dimensionless = collector absorber plate efficiency factor,
24、= collector heat remova1 factor, dimensionless = total (global) irradiance incident upon the aperture plane of the collector, W/m2 Btu/ (hr ft2) kJ/(kg OC) Btu/(lb OF) (Ib OF) dimensionless = incident angle modifier, dimensionless = number of rows of collector modules in paral- lel in the collector
25、array, dimensionless = mass flow rate of the transfer fluid through the collector during the ASHRAE Standard 93-1986 tests, kg/s (lb/hr) = the mass of the jth withdrawal of water, kg (Ib) = mass flow rate of the transfer fluid through the collector array during the solar hot water system test, kg/s
26、(lb/hr) = number of collector modules in series in each parallel row in the collector array, dimension- less = daily energy consumed for auxiliary heating in the solar hot water system, kJ (Btu) = daily energy consumed for heating in the con- ventional domestic water heater chosen for comparison and
27、 used to calculate e, kJ (Btu) = daily system hot water load defined as the pro- duct of the mass, specific heat, and tempera- ture increase of the water as it passes through the solar hot water system, kJ (Btu) = rate of energy output from the collector loop heater in series with the non-irradiated
28、 solar collector array (if used), W(Btu/hr) = daily energy consumed for parasitic power by pumps, controls, solenoid valves, etc. in the solar hot water system, kJ (Btu) = energy output.from the collector loop heater (if used) during the test, Wh (Btu) = daily net energy output from the solar collec
29、- tor and solar storage parts of the solar hot water system, kJ(Btu) = rate of useful heat output from the collector, W (B tu/ hr) = fraction of hot water load supplied by solar energy, dimensionless = ambient air temperature, OC (OF) = ambient air temperature in the laboratory dur- ing the system t
30、est, OC (OF) = ambient air temperature specified for the test solar day, OC (OF) = temperature of the transfer fluid entering the collector, OC (OF) = temperature of the transfer fluid leaving the collector, OC (OP) = mixed temperature of the water withdrawn from the solar hot water system, OC (OF)
31、= mean plate temperature of the collector ab- sorber, OC (OF) = mean plate temperature of the collector ab- sorber under non-irradiated conditions, OC = ultimate desired hot water delivery tempera- ture after the addition of supplemental energy, OC (OF) = mixed temperature of the jth withdrawal of w
32、ater, OC (OF) = temperature of the incoming cold water supply to the solar hot water system, OC (OF) = collector heat transfer loss coefficient, W/(m2 OC) Btu/(hr ft2 OF) = absorptance of the collector absorber coating to the solar spectrum at normal incidence, dimensionless = angle of incidence bet
33、ween the direct solar beam and the normal to the collector aperture, = specular reflectance of the cover plate assem- bly at an incident angle of 60, dimensionless = transmittance of the cover plate assembly to the solar spectrum at normal incidence, di- mensionless = effective transmittance-absorpt
34、ance product for the collector at normal incidence, dimen- sionless = represents a summation over all water with- drawal periods during a test day (OF) deg ASHRAE STANDARD 95-1987 ASHRAE 95 47 m 1. PURPOSE 1.1 The purpose of this Standard is to establish a uniform method of testing solar domestic wa
35、ter heating systems for thermal performance. 1.2 This Standard is not intended to beused for testing the individual components of the system. 1.3 This Standard is not intended to abridge any safety or health requirements. 2. SCOPE 2.1 This Standard applies to solar domestic water heating systems des
36、igned to heat potable water to be supplied for domestic water usage. 2.1.1 This Standard is not intended for other than solar water heating systems designed solely for domestic water usage. 2.1.2. The test procedures in this Standard are generally applicable to systems of 0.45 m3 (120 gal) storage c
37、apacity or less, and use demands on the order of 0.38 m3 (100 gal) of hot water per day, or less. 2.1,3 The test procedures in this Standard employing a non-irradiated solar collector array do not apply to an in- tegral collector storage system, a system in which ther- mosyphon flow occurs, or to an
38、y system employing a col- lectodheat transfer fluid combination which cannot be tested in accordance with ASHRAE Standard 93-1986. * 2.1.4 The test procedures in this Standard do not re- quire the solar water heating system to be subjected to freez- ing conditions. Consequently, the energy consumed
39、or lost by a system while operating in the freeze protection mode will not be determined. 2.2 This Standard provides the method of testing such systems for thermal performance. 3. DEFINITIONS accuracy: the ability of an instrument to indicate the true value of the measured physical quantity. ambient
40、 air: air in the space surrounding the thermal energy storage device or solar collectors, whichever is applicable. angle of incidence: the angle between the solar beam and the normal to the aperture plane of the solar collector. aperture plane: the projected plane at or above the solar col- lector t
41、hrough which the unconcentrated solar radiation is admitted. area, gross collector: the maximum projected area of the completed solar collected module exclusive of integral mounting means and liquid connectors. For an array of col- lectors, gross area includes the entire area of the array. auxiliary
42、 energy: see auxiliary thermal source. auxiliary fuel: that fuel used in an auxiliary thermal source. auxiliary thermal source: a source of thermal energy, other than solar, used to provide the service water heating; usually in the form of electrical resistance heat or thermal energy derived from co
43、mbustion of fossil fuels. ASHRAE STANDARD 95-1987 0754650 0011104 O beam irradiance: irradiance received from the sun without significant change of direction from the suns apparent position. collector, concentrating: a solar collector which uses reflec- tors, lenses, or other optical elements to red
44、irect and pos- sibly concentrate the solar radiation passing through the aperture onto an absorber of which the surface area may be smaller than the aperture area. collector, flat-plate: a non-concentrating solar collector in which the absorbing surface is essentially planar. collector loop heater:
45、a heater installed within the colec- tor loop when testing the solar domestic water heating sys- tem with a non-irradiated array. components: parts of the solar hot water system including but not limited to collectors, storage, pumps, etc. control: any device for regulation of the solar hot water sy
46、stem or component in normal operation, manual or automatic. domestic: refers to use in residential and small commercial buildings. drain back: refers to systems in which the fluid in the solar collectors is allowed to drain back to storage whenever solar energy is not being collected, Le., the fluid
47、 circulating pump is not operating. drain down: refers to systems in which the fluid in the solar collectors is drained from the system under prescribed circumstances. draw rate: see water draw rate. equivalent length the length of a straight section of pipe or duct causing the same pressure drop as
48、 actually occurs within the system at the same flow rate. fluid transport the transfer of air, water, or other fluid bet- ween components. fractional energy savings: that fraction of energy used by a conventional domestic water heating system that is saved by using the solar system. heat exchanger:
49、a device specifically designed to transfer heat between two physically separated fluids. Heat ex- changers can have either single or double walls. incident angle: the angle between the outward drawn nor- mal to the solar collector aperture plane and the solar beam. insolation: solar radiation incident on the solar collector. irradiance, instantaneous: the quantity of solar radiation incident on a unit surface area in unit time. irradiance, integrated average: the solar radiation incident on a unit surface area during a specific time period divided by the durati
