This Standard was prepared by the Joint Standards Australia/New Zealand Committee CS-028, Solar Heating and Cooling, to supersede AS/NZS 4234—2008.

The objective of this document is to provide methodologies to quantify the energy consumption of heated liquid systems and calculate energy savings relative to reference heaters.

Changes to the previous edition are as follows:

(a) Additional water heating technologies based on PV water heating, variable speed heat pumps and commercial applications are included
(b) The reference water heater systems used to quantify energy savings have been updated to current MEPS requirements; the main change being the increase from 3 star to 4 star for the gas reference water heater.
(c) The typical meteorology year weather records have also been updated.
(d) References to third-party software have been removed.
(e) New requirements for assessing the suitability of software packages for the application of this document.

The performance evaluation procedure defined in this document has been designed to provide a means of evaluating the annual task performance of heated water systems.

Testing of solar and heat pump water heating systems under outdoor conditions is defined in AS 2984, Solar water heaters—Methods of test for thermal performance—Outdoor test method. Outdoor testing requires a long test period (8–10 weeks) due to the need to obtain stable inputs for a range of operating conditions. The major drawback of outdoor testing is that the tests must be repeated for every variation of system configuration offered by the supplier. The procedure defined in this document overcomes the time and cost limitations of using the outdoor test standard AS 2984.

The performance evaluations are based on modelling annual performance in a range of climatic conditions using a simulation program. Performance criteria are specified for simulation programs that can be used to implement the requirements of this document.

Typical meteorological year weather data files for Australia are now based on Bureau of Meteorology satellite data from 1990 to 2016. The new weather data records indicate higher solar radiation levels in Zones 1 and 4 and higher ambient temperatures in all zones compared to the terrestrial weather data (1967 to 1987) used in previous versions of this document.

NOTE Weather data files for five Australia climate zones and two New Zealand climate zones are supplied with the purchase of this document.

The weather data files for the five climate zones in Australia are supplied free of charge to users of the document by Exemplary Energy Partners. For users of the document wishing to use weather data for other sites, additional weather data files can be obtained from www.exemplary.com.au/solar_climate_data/solar-radiation-data.php

This document evaluates the performance of water heating technologies such as Solar Thermal Collectors, Heat pumps, photovoltaic arrays, thermal storage tanks (which can incorporate integral gas or electric resistance element boosting) and in-line supplementary heating utilizing gas or electric energy sources.

The terms “normative” and “informative” are used in Standards to define the application of the appendices to which they apply. A “normative” appendix is an integral part of a Standard, whereas an “informative” appendix is only for information and guidance.