HPC Newsletter

Heat pump components development trends

Volume 25, No.3/2007

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In this issue

Heat pump components development trends Dear readers,

Heat pumps are like chains – no better than the weakest link? There has been a constant evolution of the different components in heat pumps. One major success was the implementation of plate heat exchangers; are others perhaps waiting around the corner? In this issue we look at development trends regarding different heat pump components. Enjoy your reading. Roger Nordman Editor

Heat Pump News

France legislates for warmer summers In the same way as Hong Kong and China have done, France has accepted a directive (2007-363) to shut down air conditioners when the temperature is below 26 °C. In the long run, it is expected that manufacturers will include a built-in function to follow this directive.

ASHRAE to fund CO₂ refrigeration research

For the first time, the leading US society for heating and refrigeration will support the development of CO₂ (R744) in industrial refrigeration, with a USD90 000 grant to the Washington State University for its research on heat exchangers for subcritical applications.

First heating law for renewable energy in Germany: Baden- Württemberg sets the example From 1st April 2008, new buildings in Baden-Württemberg must obtain 20 % of their heating requirements from renewable energy sources*. In its draft of an appropriate law, the government of Baden-Württemberg, is the first federal state to call for the use of solar, bio or environmental heating systems for use in water heating and space heating.

Topical Articles

Microchannel heat exchangers The air conditioning industry faces a constant challenge to provide higher effi ciency levels and greater equipment reliability. This challenge is even more difficult to meet when the goal is simultaneously to maintain equipment size and limit potential cost impact. Previous engineering solutions designed to satisfy these requirements have typically included such changes as improving individual components (e.g. higher efficiency compressors) or increasing the overall heat transfer surface area (e.g. a larger coil) to boost thermal performance. However, each of these enhancements tends to increase equipment size, cost, or both.

Development trends for heat pump components
Lorenzo Cremaschi, Oklahoma State University, USA.

Given the critical importance of energy and cost savings, the application of engineering and management principles has the potential to reshape the design of modern heat pump systems. Microchannel heat exchangers, ejectors, and injection-compressors are some of the latest more interesting developments in heat pump components that boost up the energy performance with respect to the basic heat pump cycle. In this article an overview of the current development trends for heat pump components is discussed and the performance improvement using novel, and sometimes complex and bizarre, heat pump cycles is summarized.

Trends in next-generation heat exchangers for heat pump systems

Shigeharu TAIRA, Daikin Industries, JAPAN

Development of air conditioning products to address environmental and air pollution concerns is now an imperative for the industry. Heat exchangers, which are widely used in room air conditioners, packaged air conditioners, heat pump water heaters and other applications, are one of the most important components and affect the performance, reliability (quality) and cost of the product. This paper, therefore, describes trends in the development of heat exchangers by air conditioning manufacturers, focusing on actual cases.

Compressors for Heat Pumps Mathison, Margaret M., Groll, Eckhard A., Braun, James E., Purdue University, USA

The overall efficiency of a heat pump system is highly dependent on the performance of the compressor. Compressors in heat pumps not only encounter a wider range of operating conditions than in traditional air conditioners, but also have two to three times longer run times per year than compressors for air conditioners [1]. The combination of higher pressure ratios and extended operating times present specifi c challenges for compressor manufacturers. The proposed solutions to these challenges are the subject of this article.

Packaged Air-Conditioners Suitable for Cold Areas

Nobuo KAWAI, Tooru KUBO, Tatsuya TANI, JAPAN

Annual domestic (Japanese) shipments of packaged air-conditioners were 624,000 in 1999, and reached 808,000 in 2005, showing a favourable increase. Of the shipped packaged air-conditioners, those intended for shops and offi ces accounted for 81%. However, shipments of packaged airconditioners for Hokkaido and Tohoku District amounted to over 47,000 in 2005, and are also on the increase recently. Heat pump air-conditioners have been almost inadequate, because their heating capacity is reduced with falling outside air temperature, which requires electric heaters and stoves to supplement the insuffi cient heating capacity of conventional heat pump air-conditioners.

Non - Topical Article

An overview of the industry and the market for heat pumps in Korea

Dr. Seong-ryong Park, KOREA The heat pump is one of the most effective among technologies for carbon dioxide reduction. Nevertheless, the popularity of heat pumps is not so common because of geographical, economic and technical problems. In Korea during the winter season the ambient temperature is very low (about -5 °C), and electricity is expensive. Direct heating from a boiler costs less than that of a heat pump system.
Continuous efforts have been made

by researchers for the last decade to overcome these obstacles. Nowadays, heat pumps systems for specifi ed locations such as cold areas, multi-zone and module-based systems with high performance are available in the market. Also, the development of IT (Information Technology) has enabled optimized control techniques to be developed, and the application of heat pump systems has become easier. Government policy favours GSHPs. At present, the heat pump market and industries are quite promising in Korea.