Document ID: chunk:federal_register_of_legislation:F2022C00033:reg:9:p4
Version: federal_register_of_legislation:F2022C00033
Segment Type: reg
Provision Reference: reg 9 (pt 4/9)
Character Range: 32269–34977

temperature setting of the pump controller used for no-load system operation test (clause 7.4.3.2 in AS/NZS 2712:2007) is not specified in the AS/NZS 2712:2007 test report, then a maximum value of 65°C shall be used (Tmax = 65oC and Tmax_reset = 60oC shall be used in the modelling).

     For a simple temperature difference pump controller the minimum turn off temperature difference shall be 1 K.

Piping models

     All piping shall be modelled using the TYPE 31 pipe routine.

Instantaneous gas heater defaults

     If an instantaneous gas booster has not been assessed for electrical power consumption during standby under AS 4552-2005, then a value of 10 W shall be used.  If the electrical power consumption during burner operation is not available, then a value of 50 W shall be used.

     If the startup heat loss has not been assessed under AS 4552-2005, then a default value of 0.5 MJ shall be used.

     AS 3498-2009 requires water heating to minimum of 70oC for a storage solar preheat system with an inline instantaneous gas booster when the solar preheat tank temperature is less than 55oC (clause 7 (j) (vi)).  If a gas booster trigger temperature (≥ 55oC) less than the gas booster set point temperature (≥ 70oC) is used, then specifications for the gas booster control logic shall be provided. If specifications for the gas booster control logic are not provided, the trigger temperature used for rating purposes shall be equal to the gas booster set point temperature at all times.

Stratification option for pumped circulation tanks
 The default stratification specification for a pumped circulation storage tank shall be "Uncontrolled flow pumped circulation" (AS/NZS 4234:2008 clause 3.7.4 or H3.4). For pump circulation SWHs satisfying the "Low flow criteria" (AS/NZS 4234: 2008 clause 3.7.2 or H3.2) the tank thermal stratification shall be modelled as per AS/NZS 4234:2008 clause 3.8.2 or H4.2, if:
         i. for solar preheat tanks, the collector flow return to the tank is in the top 2/3 of the tank; or

         ii. for in-tank electrically boosted solar tanks, the collector flow return to the tank is in the top 2/3 of the tank and the solar return is below any electric element; or

         iii. for tanks connected to stand alone heat pumps, the heat pump flow return to the tank is in the top 2/3 of the tank.

 For booster tanks in large SWHs where the water temperature is boosted with a separate pumped recirculation loop "Uncontrolled flow pumped circulation" shall be assumed unless:
         i. the return from the recirculation booster loop to the tank is in the top 2/3 of the tank; and
         ii. the recirculation flow rate is below 1 L/min per kW