The central air conditioning operation and energy saving control principle
in recent years, with the rapid development of China's economic and social, already became the first country, international energy demand and energy utilization efficiency is low. Facing the huge pressure of energy conservation and emissions reduction and the country's long-term, difficult goals of sustainable development, promote the whole society joint efforts in order to saving energy and reducing consumption has become the important strategy of the country. According to statistics, China in the field of building energy consumption accounts for about 30% of the total energy consumption society, and the installation of central air-conditioning buildings in its energy consumption accounts for 70% of the total energy consumption in the construction field, the number is growing. Therefore, central air-conditioning energy saving technology to reduce energy consumption, creation played an important role in the economic and social benefits, is not only the strategic needs of the country, also is the endogenous power.
2, central air conditioning system operation principle
task air conditioning system is to deal with indoor air, the air temperature, humidity, flow velocity and cleanliness and freshness of such indicators as to meet the requirements of use. Therefore, must take to the air cooling or heating and dehumidifying or humidifying and filtering processing measures, such as its corresponding equipment refrigeration units, water heater, air conditioning units, fresh air units, fan coil, circulating water pump, etc. When the room temperature and humidity or outdoor temperature and humidity change and influence of the internal heat source fluctuation occurs, first by the temperature and humidity sensors to send signals to regulator, the regulator after comparing with set point issue instructions to actuators, actuators, send cold quantity or heat will be constantly adjust to conform to the requirements.
in the central air conditioning system, in the case of chiller, water chiller consists of the supply of complete sets of equipment manufacturers, it is generally based on the principle of the air conditioning and rule by microprocessor automatic control, such as building control system integrator is no can't run to intervene on chiller itself. Chiller consists of compressor, condenser, evaporator and throttling element, the refrigerant compressor compression, compressed refrigerant entering the condenser, the cooled by cooling water, into a liquid, the precipitation heat from cooling water away, and the atmosphere in the cooling tower. By the condenser after throttling element into the evaporator refrigerant liquid evaporation absorb, keep frozen water cooling, and then frozen water into water cooling fan coil absorbs heat from the air. So, take the heat out of the room.
according to the processing equipment and processing methods of different air conditioning system can be divided into: cold spray and table type two kinds, the two types: full fresh air dc systems, the composite primary return air system and secondary return air system and bypass system. According to the regulation accuracy can be divided into different high precision air conditioning, the general precision air conditioning and comfort air conditioning. A comfort air conditioning should be in accordance with the equivalent temperature (generally 等) And our fleet concentration for design. The so-called equivalent temperature is a comprehensive index of the people feel comfortable, it combined with the dry bulb temperature, wet bulb temperature and air velocity to reflect the effect of hot and cold feeling. So, the equivalent temperature change with the four seasons have larger changes.
3, central air conditioning automatic control feature
in the air conditioning system in the long run, due to external conditions ( The wind, sunny, rain, snow, the temperature, solar radiation) And the internal conditions, Such as air conditioning equipment in the room, how many lighting switches and put into operation, and staff to increase or decrease, etc. ) Change, will be to interfere with the operation of the air conditioning system formed.
2, adjust the properties of the object
different controlled object, and under the same disturbance, is accused of quantity change process with time is not the same. Task air conditioning automatic control system is in order to overcome these interference factors, to maintain a certain temperature, humidity and air quality of air conditioning room. But the control effect not only depends on the temperature and humidity control system, more mainly depends on the rationality of the air conditioning system and air conditioning object properties.
3, the correlation of humidity
in the control of air conditioning, in most case, it is mainly to control the temperature and humidity of the air conditioning room. These two parameters are often in a regulating object to adjust the amount of two modulated at the same time, the two parameters in the process of regulating and influence each other. If for some reason the air conditioning room temperature, caused by changes in saturation pressure of water vapor in the air, under the condition of the moisture content is constant, will cause the change of the indoor relative humidity; Temperature would reduce the relative humidity, temperature, reduce the relative humidity will increase; In the process of regulating, adjusted for a parameter, but also cause the change of other parameters.
4, operation and conversion control
due to the air conditioning system is under the change of indoor and outdoor conditions throughout the year, according to a certain operation mode ( The working condition) Adjusted; When significant changes have taken place in the internal and external conditions at the same time to change the way of the adjustment, namely the conversion of operation condition.
5, the overall control
general air conditioning automatic control system in air conditioning room air temperature and relative humidity control as the center, through the working condition of transformation and air handling process each link closely linked to the overall control system. Air conditioning system of air treatment equipment start-stop should be based on the system of working program, carried out in accordance with the relevant operational procedures to deal with the various parameters in the process of adjustment and interlock control are not isolated, but closely related to the indoor temperature and humidity.