PDF《Evidence gathering – Low》

6 Contents Acronyms

5 1. Executive summary.7 2. Introduction and Context.10 3. Methodology

12 4. Current State of the Art

16 5. Market and Product Review.29 6. Standards Review

41 7. System Performance.48 8. Costs

65 9. Barriers and drivers to deployment

74 10. Gap Analysis

83 Annex A C list of standards

87 Annex B C Standard heat pump barriers

90 Domestic High Temperature Heat Pumps

7 1. Executive summary Introduction Most low carbon pathways suggest that heat pumps will play a large role in decarbonising the UK economy. The Committee on Climate Change (CCC) have suggested that the overall cost-effective uptake of heat pumps in UK homes could reach 2.3 million by

20301 . This study was undertaken by the Carbon Trust for the Department of Energy and Climate Change (DECC) to inform their evidence base on domestic high temperature heat pumps. The purpose is to help explore the role high temperature heat pumps may play in the market and inform future UK policy intervention relating to low carbon heating technologies. This study was conducted from September

2015 to December

2015 using desk- based research, interviews with experts and stakeholders, and a stakeholder workshop. Experts from

41 organisations were interviewed across both the demand and supply side. The Technology For the purpose of this study, high temperature heat pumps are considered to be products capable of producing an output temperature of at least 65°C2 . We have focussed on air and ground source heat pumps with a capacity of less than 45kW capacity. There are a number of heat pump designs capable of achieving high temperature outputs, including: ? Products with optimised design for specific refrigerants. ? Cascade systems with two separate refrigeration cycles. ? Enhanced Vapour Injection (EVI).

1 Sectoral scenarios for the Fifth Carbon Budget, Technical report, Committee on Climate Change,

2015 2 In the heat pump performance standard, BS EN 14511:2013, an output temperature of 55°C would be defined as '

high temperature'

and 65°C would be defined as '

very high temperature'

. However, in the next revision it is expected that '

high temperature'

will be re-defined as an output temperature of 65°C. Domestic High Temperature Heat Pumps

8 ? Use of natural refrigerants and sorption products. Whilst these products have been specifically designed for high temperature operation, the designs of conventional heat pumps are increasingly being improved to reach 60-65°C at reasonable efficiency. Current State of Market and Future Market Potential High temperature heat pumps are suitable for retrofit to existing properties as they can be used with existing, high temperature distribution systems (e.g. existing radiators) and are also capable of meeting hot water demand. However, as the performance of heat pumps reduces with increasing output temperature, most suppliers will first try to specify systems that can run at lower temperatures for increased efficiency (even where that requires some heat emitters to be upgraded). The current market is niche, and estimated annual sales are approximately 2% of total heat pump sales, numbering a few hundred units per year. Interviews with manufacturers, distributors and installers indicated that the products are typically specified to heat large, old, or listed properties, often off the gas grid (where the cost required to connect to the gas grid makes these heat pumps more cost competitive), and also with high domestic hot water demand. High temperature heat pumps are expected to remain a niche product in the short term. We have identified a wide range of manufacturers offering products designed and marketed as high temperature heat pumps. Over