Standards Development

Scope

This standard specifies design criteria for heating and water based cooling systems in buildings using electrically driven heat pumps for heating and cooling alone or in combination with other heat generators. Heat pump systems considered include (see Table 1):

— water – water;

— water – air;

— brine – water;

— refrigerant – water (direct expansion systems);

— refrigerant – refrigerant;

— air – air; — air – water.

Other energy sources such as waste water, massive absorbers and ice storage systems may also apply, as well as heat pump systems using more than one energy source. This standard takes into account the heating requirements of attached systems (e.g. domestic hot water) in the design of heat supply, but does not cover the design of these systems. This standard covers only the aspects dealing with the heat pump, the interface with the heat distribution system and heat emission system (e.g. buffering system), the control of the whole system and the aspects dealing with energy source of the system.

Design criteria for reversible heat pump systems for heating and cooling are included in this standard. Systems designed primarily for cooling are not within the scope of this standard.

Purpose

• The European Union aims at reducing carbon dioxide emissions rapidly over the next years. The resulting need to convert the energy supply to renewable energy sources will to a great extent be achieved by using electricity-based technology. As such, heat pump applications combined with photovoltaic systems along with thermal and electrical storage systems will play a central role in the future heating, cooling and domestic hot water supply of buildings.

With an increase in heat pump applications throughout Europe, there is an increasing need for understandable and practical methods on how to successfully design and install such systems. A revision of EN 15450, last published in 2007 has become necessary due to several facts:

• Heat pump technology has developed considerably since the last publication of EN 15450 in 2007.

• Heat pumps are capable of modulating operation and can achieve higher temperatures by selecting suitable refrigerants and compressor strategies.

• Central heat pump systems are being used as reversible devices. In many cases, a single heat pump can be used for heating, cooling and provision of domestic hot water to the building.

• Heat pumps are increasingly being combined with on-site photovoltaic systems and appropriate electrical storage as driving energy. This results in a high degree of autarky (up to 60% in heating and 95% in cooling applications).

• Multiple heat sources are increasingly being used

These aspects are to be taken into account in the revision of EN 15450. Furthermore, the standard should be revised in such a way that it remains understandable and includes practical design methods for a broad variety of heat pump applications.

The revision shall include:

- a division of the design into a preliminary and a detailed phase

- a definition and feasibility of user requirements (heating, cooling, DHW needs),

- a simplified heat load calculation,

- a simplified cooling load calculation (static method based on DS 469),

- a simplified DHW calculation based on EN 12831-3,

- the preliminary sizing of the heat pump (select the machine),

- the selection of the heat source and its feasibility (e.g. space requirements),

- the selection of a functional diagram from a list of suitable hydraulic schemata to suit the needs,

- the integration with on-site renewable energy generation.

Note: in case the WI is based on documents from other organizations than ISO/IEC, please specify it here