【 Weak current College 】 summary of the application of heat pump technology---Power By 【 China power house network 】

Heat pump units due to its energy-saving, environmental protection and the advantages of cold and warm with available, currently in the country. This is a collection in various newspapers and magazines across the country, annual data collection and on the application of heat pump technology and the paper altogether 207 article. In this Symposium as a for all teachers and students. Summary of the problem are as follows:

Air source (air-cooled) heat pump current products mainly household heat pump air conditioner, commercial modular heat pump air conditioner and heat pump chiller. Heat pump air conditioner has been accounted for sales of 40 ~ 50% of annual capacity to 400 million units. Heat pump chiller start since the early 1990s, in the hot summer and cold winter region has been widely applied, according to incomplete statistics, the region part of the city central air conditioner cold heat source heat pump chiller has accounted for 20 ~ 30%, and the application continues to expand and move to this trend. This collection of air-source heat pumps in papers 55 articles, main contents are:

1. with regard to the evaluation of air-source heat energy consumption

In order to evaluate and compare heat pump unit and other energy NUAN, approximately 30 papers related to this issue. Describes applies to heat pump unit energy consumption analysis: theory and software, according to the air conditioning cooling load, outdoor dry-bulb temperature, heat pump water temperature, using parameters such as temperature, frequency method for heat-pump cooling energy consumption throughout the year. In the winter for the heat pump can be time consuming, apart from considering air conditioning heat load, heat pump water temperature, outdoor dry-bulb temperature, relative humidity of the outside (i.e., temperature and humidity frequency) taking into account the performance of the heat pump, software engineering, and the actual consumption of energy has a better fitfor the energy evaluation provides a way.

2, air-source heat pump unit selection

The current design choice of air-cooled heat pump, often based on the calculated cooling load and thermal load, consider using coefficient and cold (hot) capacity loss coefficient, press unit nameplate calibration value Select line numbers. Because air source heat pump unit of production volume of cold (hot) with outdoor parameter changes, the method could result in the unit selection too large, wastage, or selected too small, so that the cooling (heat) levels are low, not to use requirements. To this end suggests using air conditioning hourly cooling load and thermal load and the heat pump for heating and cooling capacities of hourly change curve control selection, will be more satisfied with the results.

3. heat pump winter defrosting

Air-source heat pump heating runs, the biggest problem is when the outdoor temperature is low, outdoor side heat exchanger fin surface will frosting, (need for defrosting measures). Excerpt from the documentary, the second year of field track testing, the result is loss of defrosting or about heat pumps total energy loss 10.2% due to the defrost control methods, some 27% of defrosting function is in fin surface frosting not serious, no need to defrost enter defrosting cycle. Some methods currently used, more or less problems, such as extra defrosting actions, or need to defrost time rather than signals and other ills. The best literature of defrosting time control and maximum average heating control defrost, theoretically very innovative, but more difficult to implement. In my opinion: the use of Adaptive fuzzy thinking of defrosting control and system infrastructure, determine the indoor and outdoor air temperature, relative humidity and temperature difference between the rate of change of the fin, etc. as the input field, the amount of fuzz on the input and the fuzzy reasoning method, high machine fuzzy defrost control of simulation, this approach defrosting by comparison with the experimental data, the results and the actual situation of discrimination than anastomosis.

This method and compared to conventional defrosting method, not only lengthened the heating work time and reduces defrosting times and defrosting losses and make the unit work performance and reliability. In the outdoor air temperature is low, due to the amount of heat pump for heating in winter, you need set up auxiliary heater. Commonly used methods are indoor outlet Office heaters, this approach not only lower heat transfer efficiency, security, performance and defrosting time long, large indoor temperature drops, the use of freon heater can obviously overcome these shortcomings, this approach is the Interior side of the heat exchanger is divided into two parts, in the middle of a freon booster heater, heat pumps run in winter, the compressor discharge temperatures of Leon gas enters the Interior heat exchanger front part has some gases are condensed into the liquid. At this point the freon heater heating so that the part of the liquid evaporates into the air again, and then enter the Interior heat exchanger in the second half. Thus, relying on the entire indoor heat exchanger, heat pump for outdoor heat exchanger of absorption of heat, together with the freon heater produces heat and to the air conditioning room, complement the outdoor ambient temperature low and the amount of heating. Related literature describes KFRd-70LW heat pump air conditioner on trial, was put to good effect of auxiliary heating and defrost time reduced by 3min to 1min (outdoor temperature-1 ° c); reduced by 10min to 3min (outdoor temperature-7 ° c).

4. heat pump noise control

Single or multiple heat pump noise control. Analysis of air-source heat pump noise propagation characteristics, combined with the heat pump unit of noise control engineering instance that describes the closed sound muffling device design methods, design and governance results.

As a result of air-cooled heat pump operation, management and maintenance of comparative party so that, with the double function of refrigeration and heating, heat and power unit does not require a cooling tower, therefore, the application of more and more. But the heat pump noise is easy on the surrounding environment to produce certain effects, in recent years, Shanghai, such as heat pump noise nuisance incidents increased, has become a recent city with universal fixed source noise pollution. Knowing a single or multiple heat pump noise propagation characteristics of heat pump group of noise prevention methods that have universal relevance.

From heat pump noise, noise, heat pump noise control instance, noise control and management of the technical perspective, the heat pump noise control engineering instance has certain promotional value and significance to better solveThe heat pump unit ventilation, into the exhaust and ensure the normal operation of the heat pump, full close hush sound insulation, heat pump with A sound level noise reduction of around 20dB, as in some special occasions the heat pump noise reduction to the desired level of noise control engineering design provides a reference to an instance of success, especially in the heat pump's exhaust residual pressure is low or no specific EU pressure, in the design of acoustic noise appliance inlet exhaust system can have a concrete basis for the calculation.