IEA Heatpump Programm Annex 28




technical description


On the background of environmental challenges, a manifold of energy systems delivering building services like space heating, domestic hot water production, ventilation and cooling have been developed and are competing on the market. A characterisation of the performance and the capability of the system to fulfil requirements is a necessity.

The EU energy performance directive of buildings (EPBD), being introduced in 2006, requires means to indicate the performance of the system to make a fair comparison of different competing energy systems and to bring transparency and confidence to the consumer. In North America and Japan, Energy labelling systems, which use the same metrics, have similar objectives.
The objective of the IEA HPP Annex 28 is to focus hereby on the development of test and calculation methods for combined operating heat pumps systems as input to standardisation committees.

Heat pumps have become an attractive heating system due to significant reduction of the energy consumption of buildings. With decreasing energy consumption of the building and temperature level of the heating system, the share of energy consumption for the domestic hot water production is continuously increasing. Decisive for the performance is the overall seasonal performance factor of the system. Present standards cover only the single operation modes and do not honour process improvements by combined operation.
IEA HPP Annex 28 is to investigate the testing of the most common combined heat pump systems with space and domestic hot water heating.
The systems to be investigated include the heat pump, the hot water storage (or a one through water heater) and an optional supplemental back-up heating as shown in the following figure:
 Click to enlarge

The share of the domestic hot water consumption usually represents 10% to 50% of the total annual heating consumption.
The Annex applies to heat pumps with hydronic or air heat distribution systems and alternative or simultaneous domestic hot water production.

Objectives and results:

The objectives of IEA HPP Annex 28 according to the legal text are twofold:
  • to establish a test procedure which delivers the data necessary to calculate the overall seasonal performance factor of systems
  • to work out a simple method to calculate the seasonal performance factor for the heat pump systems
Project structure and time schedule:

The project is worked out task-shared between the participants. The projected Annex running time is 28 month (1.1.2003 to 30.4.2005).
The Annex is structured in three tasks, referring to the objectives.
  • Task 1: Systems to be investigated
  • Task 2: Development of test procedure
  • Task 3: Development of a calculation method

The tasks are worked out in national projects. Overview of the national projects



last update:22.01.2008

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