AS 4234-1994

1 - AS 4234-1994 SOLAR WATER HEATERS - DOMESTIC AND HEAT PUMP - CALCULATION OF ENERGY CONSUMPTION
4 - PREFACE
5 - CONTENTS
6 - SECTION 1 SCOPE AND GENERAL
6 - 1.1 SCOPE
6 - 1.2 APPLICATION
7 - 1.3 REFERENCED DOCUMENTS
7 - 1.4 DEFINITIONS
7 - 1.4.1 Absorber
7 - 1.4.2 Angle of incidence
7 - 1.4.3 Angle of inclination
7 - 1.4.4 Close-coupled solar water heater
7 - 1.4.5 Collector
7 - 1.4.6 Collector aperture
7 - 1.4.7 Container
7 - 1.4.8 Electricity tariffs
7 - 1.4.9 Irradiance
8 - 1.4.10 Irradiation
8 - 1.4.11 Solar water heater
8 - 1.4.12 Load
8 - 1.4.13 Heat pump water heater
8 - 1.5 NOTATION
9 - SECTION 2 PERFORMANCE EVALUATION PROCEDURE
9 - 2.1 INTRODUCTION
9 - 2.2 COMPONENT TESTING
9 - 2.2.1 Electric boosted storage vessels
9 - 2.2.2 Electric storage vessels with raised elements
9 - 2.2.3 Gas boosted storage vessels
9 - 2.2.4 Heat pump storage water heaters
9 - 2.2.5 Solar collector efficiency
10 - 2.3 WATER HEATER CONFIGURATION
10 - 2.3.1 Solar collector orientation
10 - 2.3.2 Solar storage tank auxiliary input
11 - SECTION 3 PERFORMANCE EVALUATION
11 - 3.1 ANNUAL TASK PERFORMANCE
11 - 3.1.1 Solar Water Heaters
11 - 3.1.2 Heat pump water heaters
11 - 3.2 WEATHER DATA
11 - 3.3 THERMAL ENERGY LOADS
11 - 3.4 COLD WATER TEMPERATURE
11 - 3.5 LOAD CAPACITY
12 - 3.6 PRESENTATION OF RESULTS
12 - 3.6.1 Energy savings relative to conventional water heaters
12 - 3.6.2 Documentation of simulation model inputs
13 - APPENDIX A - STANDARD OPERATING CONDITIONS
13 - A1 OFF-PEAK BOOSTING TIMES
13 - A2 SOLAR COLLECTOR ORIENTATION
13 - A3 WEATHER DATA
15 - A4 LOAD CHARACTERISTICS
15 - A4.1 Daily thermal load
15 - A4.2 Hourly Loads
15 - A4.3 Seasonal load profile
16 - A5 COLD WATER TEMPERATURE
17 - A6 NO- SOLAR TEST CONDITIONS
17 - A7 RELATIVE ENERGY SAVINGS
17 - A7.1 Reference conventional water heaters
18 - A7.2 Annual purchased energy
19 - APPENDIX B - STANDING HEAT LOSS TEST PROCEDURE FOR RAISED ELEMENT TANKS
19 - B1 SCOPE
19 - B2 PRINCIPLE
19 - B3 TEST APPARATUS
19 - B4 TEST CONDITIONS
19 - B4.1 Insulation of fittings
19 - B4.2 Air Temperature
19 - B4.3 Air Circulation
19 - B4.4 Thermostat Setting
19 - B5 PROCEDURE
20 - B6 CALCULATIONS
21 - APPENDIX C - SYSTEM CONFIGURATION SPECIFICATION
21 - C1 THERMOSYPHON SOLAR WATER HEATER
21 - C1.1 Solar collector efficiency parameters
21 - C1.2 Solar collector configuration
22 - C1.3 Collector connections
23 - C1.4 Solar storage tank
24 - C2 PUMPED CIRCULATION SOLAR WATER HEATER
24 - C2.1 Solar collector efficiency parameters
24 - C2.2 Solar collector configuration
24 - C2.3 Solar collector connections
24 - C2.4 Pump and controller
25 - C2.5 Solar storage tank
25 - C3 HEAT PUMP WATER HEATER
25 - C3.1 Flat plate evaporator efficiency parameters
25 - C3.2 Evaporator configuration
26 - C3.3 Heat pump storage tank
26 - C3.4 Heat pump condenser (wrap around coil)
26 - C3.5 Heat pump compressor
27 - C3.6 Controller (in-tank thermostat)
27 - C4 AUXILIARY BOOSTING (all system configurations)
28 - C5 LOAD PARAMETERS
28 - C5.1 Average load
29 - C5.2 Hourly load pattern
30 - C5.3 Seasonal load pattern
31 - APPENDIX D - TRNSYS SIMULATION PROGRAM
32 - APPENDIX E - SOLAR WATER HEATER TASK PERFORMANCE EVALUATION
32 - E1 NONLINEAR SOLAR COLLECTOR EFFICIENCY CHARACTERIZATION
33 - E2 OPTICAL RESPONSE FUNCTIONS
33 - E2.1 Symmetric collectors
33 - E2.2 Data table of incidence angle modifier values
33 - E2.3 Collectors with north-south and east-west symmetry
33 - E2.4 Incidence angle modifier map
33 - E2.5 Collectors with east-west symmetry only
33 - E3 COLLECTOR CONFIGURATION
33 - E3.1 Collector heat removal via heat pipe
33 - E3.2 Thermosyphon systems with collector loop heat exchanger
33 - E3.3 Serpentine riser solar collector
33 - E3.4 Thermal cut-off valve in the thermosyphon loop
34 - E4 STORAGE TANK CONFIGURATION
34 - E4.1 Over-temperature relief valve
34 - E4.2 Two auxiliary elements in a thermally stratified storage tank
34 - E5 ENERGY LOAD SPECIFICATION
34 - E6 AUSTRALIAN SOLAR RADIATION DATA (TYPICAL METEOROLOGICAL YEAR)
34 - E7 REFERENCES

Sets out a method of determining the annual performance of domestic solar and heat pump water heaters using a combination of test results for component performance and a mathematical model to determine annual load cycle task performance. Together with the Standard a software disk is provided. It contains a program for evaluation of energy consumption of the solar water heaters under testing.

This Standard sets out a method of determining the annual performance of domestic solar and heat pump water heaters using a combination of test results for component performance and a mathematical model to determine an annual load cycle task performance. The procedure is applicable to solar water heaters with integral boosting or preheating into a conventional water heater and to heat pump water heaters. Solar andheat pump water heater types not covered in the application of this Standard can be testedunder AS 2984 or AS 2813 to obtain an annual performance assessment.

First published as AS 4234-1994.