EARTH ENERGY IN THE UK

EARLY UK HISTORY Delving back in the archives, seeking some (or even any) evidence of contributions that our individual countries might have played in the development of this technology, the writer has come to the conclusion that the UK story follows the classic British pattern viz: in at the beginning, good theoretical contributions, limited practical deployment by obsessed individuals with no follow through to widespread commercial success! We are now fervently trying to address the last of these, at least in the area of ground-coupled heat pumps for delivering heating and cooling to buildings. Clutching at straws, Sumner (1976) notes “that the first mention of a ‘heat multiplier’ (or heat pump) is associated with William Thompson (later Lord Kelvin).... As one of the world’s first conservationists, he therefore outlined and designed a machine which he called a Heat Multiplier. This machine would permit a room to be heated to a higher temperature than the ambient temperature, by using less fuel in the machine than if such fuel was burned directly in a furnace.” Suffice to say that in a fossil fuel rich Britain, there was little interest in such a device at the time (i.e., 1852). Sumner reports that the only interest that was shown was for the possible cooling of public buildings and British residences in India. The notion of heat pumps for heating and cooling buildings was born. Some readers will know that Cornwall has been prominent in UK geothermal activity over recent decades through its Hot Dry Rock programme. It is opportune to offer a historical plug for the region. Earlier this year, a full-scale replica of the first steam-powered vehicle, built by the Cornish engineer Trevithick, ran up Cambrone Hill–200 years after its first run. I mention this because the current interest in Trevithick’s prodigious technical innovation reveals that his thinking ranged right across the steam cycle and into the refrigeration air cycle (Burton, 2001). Next week (Oct. 2001), there will be an international conference in Cornwall discussing the steam and air cycles. While the selftaught Trevithick was trying to find a cheaper method of producing ice, the search for replacement refrigerants for heat pumps is of immediate concern to our technology. There is active research on the topic in British universities–unrelated to ground-source heat pumps per se–but related to heat pump refrigerants in general (e.g., Butler, 2001). Moving forward in time, the following is an extract from a 1981 publication: