When it comes to heat pumps, contrary to popular conception, carbon dioxide itself is in reality a more carbon friendly gas than its competitors, explains Sanyo.
It is now widely accepted that heat pumps are a quantum leap ahead of the traditional gas-fired boiler in terms of energy efficiency. Now, the arrival of Sanyo's carbon dioxide-based heat pump is claimed to represent a quantum leap ahead of conventional heat pump heating technology.

The pioneering system, launched recently, produces around 50% less carbon than comparable gas-fired boilers, and has major performance and environmental benefits over standard heat pumps.

The launch of the system has created intense interest from installers, consultants and clients. Around 30 of the systems were sold into the UK market before the official launch. It is already well established in Japan and Scandinavia, where many thousands of systems have been successfully installed.

The technology is expected to challenge the supremacy of the gas-fired boiler and standard heat pump in the domestic and small commercial market.

The inverter-controlled system consists of an outdoor heat pump unit, containing the compressor and CO2 refrigerant circuit, linked to an indoor unit containing a heat exchanger and hot water tank. It supplies hot water for washing and can be directly connected to radiators or an under-floor system for space heating.

At the heart of the system is Sanyo's pioneering carbon dioxide-based compressor, the world's first two-stage rotary compressor operating on R744. The compressor is engineered to ensure effective load dispersion, necessary to accommodate the high working pressures generated by carbon dioxide virtually to eliminate the risk of leaks. The whisper-quiet unit operates at 45db(A) and is highly compact, saving significantly on the use of raw materials.

Importantly, the Sanyo ECO CO2 produces water up to 65°C, hot enough to be used directly in traditional radiators without the need for an expensive and inefficient electric booster heater. Conventional heat pump heating systems using HFC refrigerants generally only produce water at 45-50°C.

To deliver sufficiently hot water for use directly in domestic hot water systems they have to use an energy-hungry electric boost heater. This adds cost, dramatically reduces efficiency and increases carbon emissions.

This is made possible by the exceptional thermodynamic properties of carbon dioxide as a refrigerant and the innovative design of the ECO system. It means the system can be used as a high-efficiency drop-in replacement for existing gas-fired boiler installations, without the need for installation of expensive low-temperature radiators.

In addition to reduced carbon emissions as a result of its outstanding energy efficiency, the system has another important environmental advantage by avoiding the use of high global warming potential (GWP) HFC refrigerants.

Unlike competing systems that rely on HFC refrigerants with GWPs of between 1000 to 2000, the product uses R744 (carbon dioxide) as the refrigerant. This natural and non-toxic substance has a global warming potential of just 1 (see table).

Use of carbon dioxide as a refrigerant confers another important health and safety benefit. Because the system produces water at up to 65°C, it eliminates the risk of infection with legionella. Competing products need a special 'kill cycle' every few days, requiring a booster to generate sufficiently hot water to achieve this. This is accomplished as part of normal working with the ECO C02.

Graham Wright, who heads up Sanyo's new UK heating division, says: 'We believe the ECO C02 heat pump is a technology whose time has come. With rising energy costs and environmental concern, it delivers low-cost, high efficiency heating and hot water - without the use of environmentally damaging HFC refrigerants or diminishing natural gas.

'It beats the competition hands down in terms of carbon emissions, health and safety, running costs, performance range, and backward compatibility.'
He added: 'If the UK is to achieve the ambitious targets for carbon reduction that have been set, it is essential that the take-up of such high efficiency technology is accelerated.'

Sanyo has developed a new training course to equip contractors to install and service ECO C02 systems. The subsidised course is being held at various locations across the country from April.
It enables contractors to become an approved installer and apply for future government grant opportunities.

//Graham Wright heads up Sanyo's new heating division//

For more details on training courses, call 0845 6126364.