Document ID: chunk:federal_register_of_legislation:F2022C00033:reg:9:p5
Version: federal_register_of_legislation:F2022C00033
Segment Type: reg
Provision Reference: reg 9 (pt 5/9)
Character Range: 34738–37357

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 thermal power added by the external booster; and
         iii. the booster tank recirculation water turnover rate is less than 1 tank volume per hour.
Effective air temperature
 The effective air temperature used to determine solar collector and piping heat loss during night time (horizontal irradiation < 1 kJ/h.m2) shall be Taeff = Ta – (Ta –Tsky)/5, where Ta denotes the ground level air temperature and Tsky the sky temperature as defined by AS/NZS 4234:2008.
 The effective air temperature used to determine solar collector and piping heat loss during day time (horizontal irradiation ≥ 1 kJ/h.m2) shall be Taeff = Ta.
Dip tubes

     Note for a tank with dip (or snorkel) tube, the heat transfer between the stored tank water and the water flowing inside the dip tube usually is small compared to the heat capacitance rate of the water flowing through the tube.  In this case the temperature of the water supplied to the collector inlet pipe (or the load) shall be the tank temperature at the dip (or snorkel) tube inlet.  Evidence of any dip (or snorkel) tubes must be included in tank drawings supplied for system audits.

Height parameters for thermosyphon SWHs

Note: If a dip tube is used on the cold inlet port then the measurements Hsep and Hcold are relative to the level of the outlet of the dip tube.
Units

     The units system used in TRNSYS is metre, kg, h and kJ.  All energy transfer rate parameters must be converted from W to kJ/h (multiply Watts by 3.6 to get kJ/h).

Rounding of numerical results

     The printing of STC and Energy Savings % outputs shall use the format F5.1 as specified in the example decks.  This means that an STC rating of 20.94 will be rounded down to 20.9 in the printout and this will be taken as STC = 20.  An STC rating of 20.96 will be rounded up to 21.0 in the print out and this will be taken as STC = 21.

Division C – Measurement or analysis for TRNSYS modelling parameters

Site specific pump flow rate setting
     Pumped circulation SWHs are classified as "controlled flow" or "uncontrolled flow" systems in clause 3.7.2 of AS/NZS4234:2008.
     If a pumped SWH is claimed to be a "controlled flow" system, then documentation demonstrating how the flow rate is controlled for every installation shall be provided.  The alternative product configurations that shall be detailed in the installation manual are: