1 How climate compensators work
When the outdoor climate changes, the temperature sensor arranged outside the building transmits the outdoor temperature information to the climate compensator. According to the experience curve of outdoor temperature compensation in different situations, the climate compensator outputs a regulation signal to control the opening of the electric control valve, so as to adjust the output of the heat source, so that the output water supply temperature conforms to the water temperature of the adjustment curve to meet the demand of the end load, and realizes the balance of supply and demand of heat in the system. In the heating system using heat metering, because the heat supply control should first realize the "on-demand supply" of heat to avoid energy waste caused by oversupply, and secondly, improve the energy efficiency of the heating system, for example, according to the outdoor temperature change and the user's heat load change conditions, the heating medium parameters to achieve reasonable "low temperature heating" often significantly improve the energy efficiency of the heating system.
2 Scope of Application
Climate compensators are generally used in the heat station of the heating system, or in the heating system with direct boiler heating, and are a powerful means of local regulation. Climate compensators can be used in both direct and indirect heating systems, but they are used differently in different systems.
2.1 Hot water direct heating system
In a direct hot water supply system, the climate compensator controls the water supply temperature by adjusting the amount of water mixed in the system, and its working principle is shown in Figure 1. The climate compensator controls the temperature of the system's water supply by controlling the opening of the electric control valve to regulate the amount of bypass water between the boiler inlet and outlet pipes. When the water supply temperature value detected by the temperature sensor is within the allowable fluctuation range of the calculated temperature, the climate compensator controls the bypass valve to not operate; when the water supply temperature value is higher than the upper limit of the calculated temperature, the climate compensator controls the bypass valve to open and increase the return flow rate into the system water supply to reduce the system water supply temperature; on the contrary, the bypass valve is closed to reduce the return flow into the water supply, so as to increase the system water supply temperature.
Fig.1 The working principle of the climate control valve in a direct hot water heating system
2.2 Hot water heat source indirect heating system
In the hot water indirect heating system, the climate compensator controls the water supply temperature on the user side by controlling the water supply flow into the primary side of the heat exchanger, and its working principle is shown in Figure 2. The climate compensator regulates the bypass water volume of the heat exchanger by controlling the opening of the electric control valve on the bypass pipe on the primary side of the heat exchanger, so as to control the water supply temperature on the user side of the system. When the temperature value of the water supply detected by the temperature sensor is within the allowable fluctuation range of the calculated temperature, the climate compensator controls the bypass valve to not operate; when the water supply temperature value is higher than the upper limit of the calculated temperature, the climate compensator controls the bypass valve to open wide, the water supply flow through the bypass pipe increases, and the primary water supply flow into the heat exchanger decreases, thereby reducing the heat exchange of the system. Under the condition that the circulating water flow rate of the secondary side remains unchanged, the water supply temperature will be reduced, on the contrary, the bypass valve is closed to increase the primary water supply flow into the heat exchanger, and the heat exchange of the system is increased, so as to increase the water supply temperature of the secondary side.
Fig.2 The working principle of the climate control valve in the indirect heating system of hot water heat source
2.3 Steam heat source indirect heating system
In the steam indirect heating system, the climate compensator controls the water supply temperature on the user side by controlling the steam flow into the primary side of the heat exchanger, and its working principle is shown in Figure 3. The climate compensator regulates the amount of steam in the heat exchanger by controlling the opening of the electric control valve on the steam side of the heat exchanger, so as to control the water supply temperature on the user side of the system. When the water supply temperature value of the secondary side (user side) detected by the temperature sensor is within the allowable fluctuation range of the calculated temperature, the climate compensator controls the bypass valve and does not act; when the water supply temperature value is higher than the upper limit of the calculated temperature allowable, the climate compensator controls the valve to close and reduce the amount of steam entering the heat exchanger, thereby reducing the heat exchange of the system, and the water supply temperature will be reduced under the condition that the circulating water flow of the secondary side remains unchanged; on the contrary, the bypass valve is opened to increase the amount of steam entering the heat exchanger, and the heat exchange of the system is increased, so as to improve the water supply temperature of the secondary side。
Fig.3. The working principle of the climate control valve in the indirect heating system of steam heat source
3 Energy saving analysis of climate compensators
In the design of the traditional heating method, the basic heat consumption through the envelope is calculated according to the one-dimensional stable heat transfer process, that is, it is assumed that the indoor and outdoor air temperature and other heat transfer process parameters do not change with time during the calculation time. In fact, the outdoor air temperature fluctuates with the seasons and diurnal variations, which is an unstable heat transfer process, and the temperature variation is shown in Figure 4. However, due to the complexity of the calculation of the unstable heat transfer process and the difficulty of controlling it in actual operation, the stable heat transfer calculation method is adopted for general buildings in traditional engineering design.
Figure 4 is the outdoor hourly temperature of one day, Figure 5 is the outdoor hourly temperature of Jinan City from November 15 to March 15 of the following year (a total of 121 days, 2904 hours), the meteorological data used here comes from the Medpha software developed by Tsinghua University, which is based on the theoretical research results of Academician Jiang Yi of Tsinghua University for many years, and can simulate various types of hourly meteorological data in 193 cities (regions) across the country based on the principle of hourly meteorological model based on 30 years of measured meteorological data. As can be seen from Figure 4, the outdoor temperature is constantly changing at every hour of the day, and the temperature is often higher than the calculated temperature for outdoor heating, because the mainland code stipulates that "the daily average temperature for heating outdoor temperature shall be calculated using the average daily temperature of the calendar year and not guaranteed for 5 days." Therefore, the heat load calculated according to the traditional stable heat transfer method is often greater than the actual heat load required, so the indoor temperature is too high, and the window has to be opened to cool down, which not only wastes energy, increases costs, but also affects indoor comfort and human health.
However, with the emergence of the energy crisis and the improvement of people's requirements for indoor comfort, especially the emergence of modern high-tech energy-saving products - climate compensators, all the problems that arise according to stable calculations will be solved. The climate compensator measures the outdoor temperature according to the temperature sensor installed outdoors and automatically adjusts the water supply temperature according to the change in the outdoor air temperature (see Figure 6) to ensure a comfortable indoor temperature and minimum energy consumption, thus achieving "heating on demand", which not only reduces user costs, but also improves indoor comfort.
The function of the climate compensator is to keep the indoor temperature constant by adjusting the opening of the electric valve so that the water supply temperature always changes with the temperature of the outdoor air.
As can be seen from Figure 6, the outdoor temperature is just opposite to the water supply temperature, the water supply temperature is low when the outdoor temperature is high, and the water supply temperature is high, which can not only ensure that the indoor temperature remains constant, meet the comfort requirements, but also realize energy saving and consumption reduction.