major role

major role by using renewable energy as well as power generated by renewable energy sources such as wind and hydro.
The Tokyo Electric Power Company has been one of the forerunners in the use of heat pumps in several sectors of society. They led the way and played a key role in the success of heat pump and air conditioner use in Japan. In his keynote presentation, Mr Katsuhiko Narita discussed how heat pump technology has contributed to Japan’s modernisation. Being a Japanese champion in promoting heat pump technology, he described the entire history of heat pump technology, starting in the 17th century. During the last decade, global warming has become a major concern. Protecting resources and the environment is more relevant than ever, while at the same time, a growing number of people need to improve their living conditions, and the need for more comfort continues to grow. Humanity must reflect on how it uses its energy resources and on its commitment to sustainable development.
Mr Narita told the audience that against the background of future constraints on resources and the environment, heat pump technology will play a major role in the 21st century. He considers further improvement in heat pump technology and an expansion of its range of applications to the very realistic possibilities. Recent technical progress shows that air-source heat pumps can achieve a Coefficient Of Performance (COP) of nearly 6. This is the result of the so-called Top Runner initiative, aimed at improved equipment performance. More can and should be done to popularise heat pump technology in mature markets. It creates a pleasant urban living environment. Wider use of heat pump technology should be promoted as a matter of policy. A social system that effectively takes advantage of the diversity in time and temperature of its energy resources for heating and cooling buildings will be able to create a more pleasant urban living environment for its members.

Ground-source

Ground-source heat pumps Ground-source heat pumps have become a success story in several countries and climates, especially in colder regions. Market growth estimates range from 10 to 30% annually. Development of this technology has made significant progress during the past decade. However, further improvements in designing and reducing costs can be made. Reduction of initial cost has mainly been achieved through improved performance, which allows smaller, less costly heat exchangers, and more accurate design analyses. The conference devoted an entire session to this topic.
Ground-source heat pumps have not only seen significant market growth and broadened application; they are becoming recognised as a cost-effective standard for energy conservation. Key factors behind this success are soundness of the technology, improved design and installation infrastructure and the response of the heat pump industry. Current developments focus on five areas: • reducing initial costs of ground heat exchangers; • determining soil thermal properties; • modelling ground-source heat pump systems; •development of hybrid systems (ground heat exchanger combined with above ground heat rejecter/ absorber); • further development of design methodologies; •faster, lower cost pipe-joining methods; •new pumping configurations (variable speed, multiple and zoned on-off pumps).
In the US, there are three ARI certification standards, which rate so-called water-source heat pumps (water source, groundwater source and ground-source closed loop). The worldwide installed capacity and energy produced with ground-source heat pump systems is estimated at 6,675 MW and 23,270 TJ annually

compression cycle

compression cycle, which uses a rotary vane compressor with oil cooling, needs additional research and development. Given the large retrofit market potential for houses with hydronic heat distribution, scroll compressor manufacturers might do well to take up the challenge of developing specific products for this market.
Working fluids Much research has been and continues to be carried out in the field of new and alternative refrigerants and their application in air conditioning, heat pumping and refrigeration. Readers of this newsletter have been kept up to date on this topic. It might by now be superfluous to emphasise the importance of selecting the optimum refrigerant so as to achieve the design performance of a system under safe and environmentally benign operating conditions. It is obvious that the air conditioning and refrigeration industry have been impacted by environmental regulations to an extent not heard of before.
Under current circumstances, the conclusion is that no single fluid can be recommended as the best optimum solution for air conditioning, heat pumping and refrigeration systems. This means that designers are continuously faced with the problem of evaluating several refrigerants and trying to select the best one for any specific application. However, it is expected that in future environmental factors will increasingly influence the selection process.