02.01.2009
First results show Sanyo CO2 Heat Pump delivers exceptional efficiency in UK conditions





Results from the first UK installations of Sanyo’s ground-breaking carbon-dioxide-based heat pump heating system reveal that it delivers outstanding efficiencies in British climatic conditions, reports Richard Tyson, managing director of Oceanair Distribution.

The new refrigerant-based heating technology uses an advanced air-to-water heat pump to deliver low-cost hot water for use in heating and domestic supplies in residential and small commercial premises.

As reported last month (News Focus), unlike other heat pump-based heating systems operating on HFC refrigerants, the carbon dioxide-based Sanyo system produces water up to 65deg C, hot enough to be used directly in showers and baths without the need for an electric booster heater, keeping energy costs and emissions low.

It can also be used with conventional radiators, unlike some competing systems which require special low temperature rads to work effectively.
The system has achieved considerable success in Japan and Scandinavia, but to date the only field performance data available has been based on conditions particular to those countries. This is characterised by very low winter temperatures, down to -26deg C, and not reflective of the milder winters experienced in the UK.
With the completion of the first UK installations of the technology, the opportunity arises to assess for the first time its performance in British climatic conditions. The first test site chosen was a solid stone-walled, 200-year-old three-bedroom cottage, sited on Exmoor. The outdoor unit was installed in a temperature-controlled workshop, allowing the temperature of the “outside” air to be controlled between +20deg C and -2Deg C.
The existing oil-fired boiler was quickly replaced with a 9kW Sanyo unit, and the system commissioned and set to run. The heat pump took over providing for all heating and domestic hot water needs of the home just in time for the cold weather in November.
The carbon-dioxide-based unit supplies water to the radiators at 65deg C and enough hot water for the owners’ needs, without the need for any electrical boost heaters.
The system was monitored using a ClimaCheck performance analyser. The results have confirmed expectations for excellent performance and efficiency. A COP of 3.7 was recorded with water at 35deg C and an outside temp of 15deg C; in addition, a COP of 2.71 was recorded with a flow temperature of 65 deg C, and an outside temp of 7 deg C.
There are now a number of new sites coming on line which will enable us to further confirm the efficiencies of the system. However, on the strength of the field results so far, we have every confidence that the Sanyo ECO CO2 system delivers exceptional performance in UK conditions, and that the product is set to become a market leader against which others will benchmark themselves.




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