It is now well over 10 years since EA Technology began studies to examine the feasibility of micro CHP. Initially the efforts of technology developers were focused on overcoming the fundamental engineering challenges, such as achieving extended operating hours without service intervention. Further development work addressed the reliability of ancillary components as well as the practicalities of manufacture at a realistic cost. A number of micro CHP products are now at a stage where they face perhaps the most significant challenge of all - that of fulfilling the demands of domestic consumers.

All too often this has been the undoing of novel technologies; witness the failure of heat pumps and condensing boilers to achieve significant market penetration. If micro CHP is to fulfil its potential for energy savings, environmental benefits and economic advantage, we need to be absolutely confident that initial products will perform adequately and, equally importantly, that they will be perceived in a positive light by potential customers. It is for this reason that field trials of the WhisperTech unit have been undertaken in UK homes over the past three years. Objective, independent evaluation of performance by EA Technology has led to recommendations for improvements, which have been incorporated into the evolving product at each stage. This has resulted in a product which now appears to meet the requirements for a target market sector comprising homes with sufficient energy bills to provide the savings necessary to recover the initial investment.

During the 2002-2003 heating season, trials of 30 units were undertaken in a range of homes in the Chester and Ipswich areas. The objective of this trial was to gain further installation and operating experience of micro CHP and to identify an appropriate market sector for the initial commercial launch.

This paper describes the installation and performance of a micro CHP system in one of these trial homes. The system was installed as a replacement for the existing gas boiler in a conventional gas-fired central heating system and achieved energy savings in line with expectations. Based on a total energy bill of £1000 per annum (£550 gas, £450 electricity) total savings of around £200 were projected for the whole year’s operation. Subjective criteria such as noise and physical size and appearance were viewed positively by all the trialists, although it was generally felt that the micro CHP unit should be placed in a utility room, rather than kitchen area.

Although the system operated satisfactorily, a major area of concern remains the reliability of any new product and early failures could prove extremely damaging to the entire industry. It is for this reason that initial units are equipped with remote diagnostics which alert the service provider (in this case the manufacturer) if the unit is operating outside normal parameters. This allows pre-emptive service before a fault occurs and proved most effective in providing customer confidence in the systems.

Of the trialists responding to customer satisfaction surveys, around 80% expressed a desire to retain the system after the completion of the trial, although some are unable to do so for practical reasons.

Following the successful outcome of this trial, a cautious market launch is being proposed with 400 units being installed in a clearly targeted market sector during the latter part of 2003. It is expected that the units will be installed in larger, new family homes in conjunction with a thermal store. This configuration is intended to enhance the performance of the unit and provide a well designed package of compatible components, hopefully overcoming some of the installation shortcomings identified in existing homes. As this market becomes established, alternative configurations are expected to be applied to other market sectors including the numerous existing homes in which micro CHP can make a substantial impact.

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