PDF Publication Title:
Text from PDF Page: 005
TECHNICAL REPORTS Table 1 Characteristics of natural refrigerants Refrigerant CO2HydrocarbonAmmoniaWaterAir Chemical properties Thermophysical properties Global environmental property Toxicity/flammability Material deterioration Chemical stability Moderate boiling point Capacity per unit volume Theoretical COP Moderate discharge temperature Ozone layer Δ Δ Δ: Unacceptable (shadowed) Δ Δ Δ Δ Δ/ ** Δ/ ** Δ/ * Warming * Evaluated with air-conditioners/water heaters. : Acceptable ** Evaluated for source-of-heat temperature at low/high Δ 3.2 Targets of R&D Looking at CO2 and hydrocarbons in particular, special attention must be paid to the following two characteristics for their use as refrigerants in heat pump systems. CO2: because it has a low boiling point, systems will have to be designed to endure service pressures of 100 to 150 atmospheres, as the refrigerant exceeds the critical point. Hydrocarbons: because hydrocarbons are flam- mable, it is necessary to take measures to reduce in the amount of refrigerant, to prevent leakage, and to elimi- nate the sources of ignition for the elimination of acci- dents when handling the material for repair and dis- posal after use. Apparatuses that use these refrigerants have al- ready been marketed. The target of R&D activities in this sense is to improve the performance of existing apparatuses or to expand the application field by de- veloping new types of apparatuses. 4. Development of Flon-free Heat Pump Systems The following descriptions refer to an outline of R&D activities aimed at developing flon-free heat pump systems that are underway as part of the NEDO (New Energy and Industrial Technology Development Or- ganization) project and the challenges and present circumstances related to major element devices incor- porated in heat pump systems. 4.1 Participation in the NEDO development project for next-generation, flon-free apparatuses Mitsubishi has participated in the two NEDO pro- jects described below to promote the basic technologi- cal development of next-generation, flon-free appara- tuses. (1) Double-stage compressor heat pump water heaters for cold district We conducted an R&D program (FY2005 to FY2006) under the theme of “double-stage compressor heat pump water heaters using CO2 refrigerant for cold district” in compliance with the target of “improvement in efficiency and down-sizing of high-efficiency water heaters” of the Strategic Development of Energy Con- servation Technology Project. The ratio of suction pressure (low pressure) of the compressor to the discharge pressure (high pressure) is large and subjects the compressor to harsh operating conditions in cold district where the lowest tempera- tures range from -10 to -20°C, which theoretically low- ers both the water-heating capacity and the coefficient of performance (COP). For this reason, this R&D fo- cused on the improvement of the water heating capac- ity and COP. The performance and reliability were to be improved by a mechanism that includes the compres- sion stroke divided into two stages and the refrigerant injection at intermediate pressure. In addition, im- provement in the thermal insulation performance of the hot-water tank and development of a high-efficiency gas cooler (heat exchanger) were also included in R&D activities for a higher COP .(2) (2) Multi-air conditioners for buildings We have also been developing multi-air condition- ers for buildings using a CO2 refrigerant as part of the development of Non-fluorinated Energy-Saving Refrig- eration and Air Conditioning Systems for Business Use under the “Development of Non-fluorinated En- ergy-Saving Refrigeration and Air Conditioning Systems (FY2005 to FY2007)”. This development program is characterized by aiming at high performance systems through the com- bination of a recovery function for cooling exhaust heat, an energy reutilization function with a power recovery expander and gas cooler radiation mechanism that Mitsubishi Electric ADVANCE December 2007 3PDF Image | Heat Pump with Natural Refrigerants 3041
PDF Search Title:
Heat Pump with Natural Refrigerants 3041Original File Name Searched:
vol120.pdfDIY PDF Search: Google It | Yahoo | Bing
CO2 Organic Rankine Cycle Experimenter Platform The supercritical CO2 phase change system is both a heat pump and organic rankine cycle which can be used for those purposes and as a supercritical extractor for advanced subcritical and supercritical extraction technology. Uses include producing nanoparticles, precious metal CO2 extraction, lithium battery recycling, and other applications... More Info
Heat Pumps CO2 ORC Heat Pump System Platform More Info
| CONTACT TEL: 608-238-6001 Email: greg@infinityturbine.com | RSS | AMP |