Air cooled heat pump

Air cooled heat pump is one or more hosts in parallel, connected to the air conditioning terminal of the whole building through water pump and water pipe; it is mainly composed of air-cooled heat pump host, expansion tank, water pump, water treatment device, water filter, pipe valve, air-conditioning terminal, etc. As the cold and heat source of central air conditioning, the air-cooled heat pump chiller and heater unit has the advantages of one machine for two purposes. At least a four-way reversing valve is added inside the unit, which can realize the switching of refrigeration and heating conditions, and improve the utilization rate of the unit. When cooling, the condenser adopts air cooling, which saves the cooling water system required by water-cooled chiller; when heating, uses heat pump operation mode. In summer, the unit is in refrigeration state, and the refrigerant flow is as follows: compressor exhaust port high temperature and high pressure gas → four-way reversing valve → fin type heat exchanger high-pressure supercooled liquid → one-way valve 1 → liquid storage tank drying filter → sight glass → expansion valve low-temperature and low-pressure liquid → one-way valve 4 → evaporator low-temperature and low-pressure gas → four-way directional valve → gas-liquid separator → compressor suction port. In winter, the unit is in heating state, and the refrigerant flow is: high temperature and high pressure gas at compressor outlet → four-way reversing valve → high-pressure supercooled liquid in evaporator → one-way valve 2 It is shown that: liquid storage tank → drying filter → sight glass → low temperature and low pressure body of expansion valve → check valve 3 → fin type heat exchanger → low temperature and low pressure gas → four-way reversing valve → gas-liquid separator → suction port of compressor. 2、 VRV system is a direct expansion air-conditioning system that can adapt to the load change of each room by changing the refrigerant flow. By controllingThe refrigerant circulation capacity of the compressor and the refrigerant flow into the indoor unit can meet the load and output of the cooling and heating demand of the system. Principle of VRV: VRV system is mainly composed of indoor unit, outdoor unit, refrigerant pipe and control part. The indoor unit is the end device of VRV system. It is a unit with evaporator and circulating fan. It has the same principle as our common split air conditioner indoor unit. When the load demand of the whole system decreases or increases, the outdoor unit controls the refrigerant circulation of the compressor. In VRV system, there are two essential parts: 1: variable frequency compressor; 2: electronic expansion valve. At present, intelligent variable frequency multi line system is widely used in China. This system generally adopts double compressors, one constant frequency and one variable frequency. When some indoor units are turned on, the energy efficiency is higher than that at full load. Under partial load, the outdoor unit can operate within 135% of the capacity ratio coefficient of indoor and outdoor units (Note: most manufacturers do not allow over allocation of 130%). 3、 Comparison of air-cooled heat pump and VRV multi split system cooling mode: multi split system: refrigerant → air, one-time heat exchange, high heat exchange efficiency. Air cooled heat pump: refrigerant → water → air, secondary heat exchange, loss. Application situation: multi online system: it can be used from small scale to large scale, but it has the limitation of pipe length. Air cooled heat pump: widely used in medium and large-scale places design content: multi split system: layout of indoor and outdoor units, refrigerant pipes and condensate pipes. Air cooled heat pump: main engine, water pump, air conditioning boxFan coil unit, expansion water tank design. Pipeline length: multi split system: there are some restrictions on the distance elbow making machine between indoor and outdoor units and the height difference, so it is necessary to consider the location of outdoor units, system division, pipe length attenuation and other related factors in the design. Air cooled heat pump: there is no limit on the length of main engine and end pipe, but the longer the pipeline is, the greater the capacity of water pump is required. Comfort: multi split system: poor comfort, low supply air temperature, damage to the human body's own thermal balance, resulting in a very uncomfortable feeling, leading to the occurrence of "air conditioning disease" of "indoor personnel"; the air is dry in winter, and the humidity is too high in summer; it can effectively filter and purify, with high cleanliness. Air cooled heat pump: using water as the transmission medium, the air supply temperature is appropriate Vertical square duct seam closer (cold source 7-12 ℃, air outlet temperature 10-15 ℃);? Heating without electricity, will not damage the humidity;? Good air distribution, high comfort, unable to effectively filter and purify. Noise: multi split system: low noise of indoor unit and low noise of outdoor unit. Air cooled heat pump: the outdoor unit is noisy; the water pump is noisy initial investment: multi split system: the equipment price is high. Air cooled heat pump: lower equipment price. Individual operation: multi split system: under partial load, the combination of fixed frequency compressor and frequency conversion compressor can realize high energy saving. Air cooled heat pump: the minimum starting capacity is large, causing inconvenience and low energy saving under low load. Temperature: multi line system: high temperature control square duct machine accuracy. Air cooled heat pump: low precision of temperature control. Control: multi online system:VRV system both outdoor and indoor units are equipped with electronic expansion valve and computer control board, which is relatively more suitable for connecting to building automation system. Air cooled heat pump: the output of main engine, water pump and terminal is analog signal. If it needs to be connected to building automatic control system, its control system is relatively complex, which will increase the cost. Cost: multi online system: VRV system (about 400 yuan / m2). Air cooled heat pump: air cooled heat pump system (about 350 yuan / m2). Antifreeze: multiple on-line system: there is no antifreeze operation problem in winter. Air cooled heat pump: Antifreeze Operation Problem in winter.