Study And Development Of HVAC Based On Energy

With large buildings emerging and central air conditioning universal applicating, building energy consumption increase greatly. According to statistics, the HVAC (Heat Ventilation Air Conditionar) energy consumption achieves more than half of building energy consumption. At present, the HVAC's traditional control method in large-scale public buildings is BAS (building automation systems). The HVAC equipments are respectively monitored by BAS, so it's difficult to achieve optimal control effect, and difficult to obtain maximum energy saving. Therefore, research on energy saving of HVAC has important significance.By analyzing the traditional HVAC control system's shortcomings, we put forward a control method with the parameter of energy for global energy saving. In the paper, we theoretically expound the principle of this method, and design new control systems. Experiments and applications show that this method improves HVAC energy saving's effect.Firstly, according to law of energy conservation, we use refrigeration station's output cooling load and temperature of the building indoor and outdoor to establish cooling load's model of the building, and then adopt this model to complete the terminal building cooling load's real-time calculation. According to building standard cooling load and detailed analysis of the cooling load, we propose a new dynamic energy index as a control parameter of HVAC.Secondly, bases on the traditional control method of HVAC, cooling load of terminal building, and the dynamic energy indexe, we complete HVAC equipments' separated control algorithms and united control algorithms. According to the demand of terminal cooling load and traditional control methods of VWV, we design new pump control algorithms, which can meet the building's need and realize the lowest output load of station, this algorithm avoid pump's output excessing overshoot and pumping repeated adjustment, etc.s. We use variable flow pump data, chiller water pipe's storage load and terminal cooling load's demand realizing the chiller energy control algorithm. Through the analysis of the effect and efficiency of COP and related factors, we establishe the chiller and the cooling tower's mathematical models. We use these two models to complete the chiller and cooling tower's energy consumption analysis, and complete their united optimal control algorithm's design.Thirdly, based on the energy as parameter of energy saving control method, we complete the energy-saving control system's development. We use Microchip Inc's MCU design the Controller bases on TCP/IP and RS485 Network, which includes chiller, chiller pump, cooling pump, and cooling tower's ventilator. This development boards include all HVAC data sampling, detect and control all devices in the station. In the software design, the methord of embedded operating system has been used; it improves the software design's speed and increases the software's stability, reliability, and expansibility. In the hardware design, the development boards include HVAC data sampling, Control cabinet's signal detection, TCP/IP communication, RS485 communication, RTCC, outside memory, and so on. In electromagnetic interference (EMI) design, we take a series of measures to improve the system hardware's stability and capacity of resisting disturbance. Such as separating digit circuit's ground and analog circuit's ground, the frequency compensation of power, filteration of input signal, separating of high power and low power, isolating big electromagnetic interference components, and so on.Finally, by analyzing HVAC's energy-saving situation using this methord, the analytic data shows the HVAC system has 27% energy saving, we use the development system in a project, which the HVAC's chiller pump has been reconstructed. The data shows that the chiller pump has 30% energy saving, it has good effective.