How to reduce CO2 emissions in cities?

Dec. 09, 2015 | Green HP: Towards a decarbonized energy system with heat pumps

The building sector is one of the main consumers of energy in Europe. This fact has prompted the EU-funded development of a heating system for use in urban areas that can interact with future smart energy infrastructures.

Carbon dioxide (CO2) levels emitted from European cities must be dramatically reduced to meet current EU 2030 goals or targets outlined in several EU directives. One key solution for turning our high-populated cities to sustainable living areas, is by renovating and retrofitting buildings with low emission heating systems.

Heat-pump technologies can cover the energy demands of residential and commercial applications as well as industrial processes without a loss of comfort or quality. They offer a real opportunity to close the gap between the current ambition level and the climate and energy targets of the EU and the world.

The EU-funded project 'Next generation heat pump for retrofitting buildings' (GREENHP) is addressing these challenges by developing an advanced heating system with minimum environmental impact using air/water heat pump technology that is both economically and environmentally viable.

Due to limited space in cities, heat pumps should be integrated into existing buildings and must be compatible with pre-existing heating systems. In addition, installation and running costs must be sufficient to make the changeover to heat pumps in urban areas economically attractive.

The GREENHP project is designed to be retrofitted to multi-family or commercial buildings with a living area of around 600 metres squared. It is based on a variable capacity air/water heat pump and is capable of supplying up to 30 kW of heat for space heating and domestic hot water. Air/water heat pumps are cheaper than ground-coupled heat pumps as they are much easier to install.

Moreover, researchers are developing the concept for combined operation with a photovoltaic and solar thermal system and investigating the use of propane as an alternative refrigerant. They will also demonstrate how an air/water heat pump unit can interact with large energy systems, such as a smart grid environment in particular. In addition, the use and storage of energy will be rationalized.

The research undertaken in this three year project is based on a comprehensive multi-level research approach ranging from innovative heat pump components to advanced system integration concepts.

The main research objectives on the three research levels of the GreenHP project are as follows:

Component level:

• New heat exchanger concepts based on brazed aluminium micro-channel heat exchangers including bionic refrigerant distribution

• New compressor concepts

• Optimized fan and air flow systems including advanced anti-icing and defrosting methods

Unit level:

• Refrigerant charge reduction

• Heat pump design enabling high efficiencies

System level:

• Building integration concepts including a photovoltaic and solar thermal system

• Holistic control strategies for the system

• Energy management concepts for smart grid integration

Potential Impact:
The expected results of the GreenHP project include:
 to prove that air/water heat pumps can be a most significant future heating and cooling technology for retrofitted buildings in densely populated areas and cities
 to demonstrate the possibility to substantially reduce refrigerant charges in air/water heat pumps thus promoting the use of alternative refrigerants
to show how air/water heat pumps can be integrated into larger existing systems with other renewable energy technologies
 to demonstrate how controls of an air/water heat pump unit should work in a ‘Smart Grid’ environment
 to highlight the use of air/water heat pump units for heating and cooling in multifamily and commercial houses
 to pave the way for widespread adoption of the system in urban areas

The potential impact of the GreenHP system comprises:
• to enhance significantly the energy efficiency of heating and cooling systems for the use in multi-family houses in urban areas
• to enhance the application range of heat pumps by focusing on high capacity air/water heat pumps and heat pumps with alternative working fluids including their cost effective integration into larger systems
• to rationalize the use and storage of energy

The consortium consists of nine partners: three research institutes (Austrian Institute of Technology, KTH, Fraunhofer ISE), five industrial partners (Emerson Climate Technologies, Hesch-Schröder, Ziehl-Abegg, AKG and Gränges, and one association (European Heat Pump Association).

Project partners are confident that the GREENHP heat pump system will have a major impact on the European building sector by providing a new technical solution for efficient heating. To make the greatest impression possible, the consortium will disseminate its results not only to heat pump manufacturers, but also architects, urban planners, installers and end users. Therefore, GREENHP will make a significant contribution to a sustainable energy system and eventually, cities free of CO2 emissions.

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