Flexible friends

It is acknowledged that air-to-water heat pumps are an efficient and practical solution for providing heating and hot water in our homes, but to get the best efficiencies it is vital that the correct heat pump is specified for an individual application, says Nancy Jonsson.
The benefits of air-to-water heatpumps are now widely understood. They are a highly energy efficient solution for both new- build housing and refurbishments that can reduce carbon emissions by up to 50% and have much lower running costs – especially in off-gas areas – when compared with traditional heating systems.
For house builders, air-to-water heat pumps can help meet ever-tightening Building Regulations and higher levels of the Code for Sustainable Homes. For social housing providers, these systems can help meet legislative requirements, reduce energy consumption and carbon emissions, and also helping to reduce tenants’ fuel bills in both new and refurbished homes.
Advances in technology – and efficiencies, however, mean it is no longer a case of ‘one-size-fits all’ when it comes to air-to-water heat pumps. The wide range of products on the market can vary significantly, and it is important to pick the right system to suit each project’s needs if maximum levels of efficiency are to be achieved.
There are split and monobloc ranges, high temperature and low temperature systems, and specialist heat pumps designed for multi-occupancy buildings or commercial applications. In addition, there are now smaller capacities available, specifically designed for today’s highly insulated new-build homes.
Low temperature air-to-water heat pumps are most suitable where an existing house is being refurbished, incorporating improved insulation levels and replacing heat emitters, or ideally in new-build homes. Operating most efficiently when generating low flow temperatures, these applications mean that the emitters can be suitably sized to deliver the required heat at the lowest possible flow temperatures. Underfloor heating systems can be designed to operate with flow temperatures as low as 35°C. Heat pump convectors are also designed to operate at similar low flow temperatures while low temperature radiators typically require 45°C.
There are two types of low temperature heat pumps available: split refrigerant systems consisting of an outdoor unit and an indoor unit, and monobloc heat pumps that have a sealed refrigerant circuit contained in the outdoor unit.
Split refrigerant systems
Low temperature split refrigerant systems are the most versatile of all air-to-water heat pumps and the latest models have very high efficiencies for the highest possible running cost savings. They are available in a wide range of capacities to suit every size of home, providing maximum installation flexibility. Depending on the capacity, the outdoor unit can be situated up to 30m away from the property, and some can even be sited up to 70m away, making them ideal where aesthetics are of paramount importance.
Monobloc systems
Where internal space is at a premium, or where smaller capacities are required, a monobloc system may be more suitable. Lower capacity monoblocs (6kW and 8kW) are particularly suitable for smaller properties and are designed specifically for the UK housing sector, targeting fuel-poor, off-gas properties.
Monobloc air-to-water heat pumps are ideal for installers making their first move into renewable heat pumps because refrigerant-handling qualifications are not necessary for installation. Products such as the Daikin Altherma monobloc offer an easy installation for first time installers since all the key hydraulic components such as the circulation pump and expansion vessel are factory-fitted in the outdoor unit.
It is also worth bearing in mind that almost 30% of the UK’s housing stock was built before 1944 and is classed as being ‘hard to heat’ – solid walls, high ceilings and poor thermal design. In these properties, particularly where the householder wishes to retain the existing heat emitters, a high temperature system could be a better option when coupled with insulation improvement measures.
For such properties, specifiers and installers may wish to consider the option of a high temperature heat pump. Typically they are designed to provide flow temperatures of up to 80°C using advanced refrigerant and compressor technology and without the use of an additional immersion heater. High temperature heat pumps are often suitable as a direct replacement for traditional boiler systems.
For apartments or high density housing, a multiple-occupancy system may be better. The latest heat pump systems allow independent control and billing of heating/hot water systems within each individual home, with the whole building system powered from community-based outdoor units.
An excellent alternative
Air-to-water heat pumps are clearly an excellent alternative to traditional heating and hot water systems in both newbuild and refurbished housing. But like any technology, it is vital both for public reassurance and the industry’s reputation that any given application is going to meet the highest standards.
So, whatever the need, it is vital that the correct system is specified in order to maximise energy efficiency for any given application.
[author image=”https://www.installeronline.co.uk/wp-content/uploads/2013/03/nancyjohn.jpg” ]Nancy Jonsson is Product Manager, Heating and Renewables, for Daikin UK. She has worked in the heating industry for 12 years, during which time she has helped develop a number of new products and technologies such as boilers, solar thermal systems, underfloor heating, heating controls and, more recently, heat pumps. Before joining Daikin, Nancy worked for a number of leading manufacturers in the HVAC industry. Her current role involves defining new product requirements in response to installer feedback and market trends.[/author]

Form not found, form id :279