The relationship between air conditioning and floor heating and thermostat

Air conditioning is one of the most common equipment in life to adjust the temperature difference between indoor and outdoor, generally driven by electricity. The nature of thermal power is carbon emissions, so energy-saving products emerge at the right moment, among which floor heating with heat source water is the most direct effect and widely used. Air conditioning with its can be in a short time of rapid refrigeration or heating, favored by the majority of users, but it has more energy consumption, occupying area, difficult maintenance and other shortcomings. Floor heating has many advantages, such as health care function, comfortable health, economic energy saving, good thermal stability and long service life, but it also has the most direct disadvantages, the heating speed is slow, can not make the room quickly heat up in a short time. Based on the advantages and disadvantages of air conditioning and floor heating, China's thermostat manufacturers, represented by E-TOP, designed a dual-use temperature controller of air conditioning and floor heating, which has made relative optimization in temperature regulation and energy saving. The thermostat has undergone three updates, the first generation is electrical, the second generation is electronic, and the third generation is intelligent. The so-called intelligent temperature controller is the application of new control model and NUMERICAL control chip. E-top adopts HI67F489 as the main control chip, and customized a special code breaking screen for supporting use. Through software programming, the operation of the temperature controller is more simple and convenient, which is convenient for users to operate better. However, the power consumption of the central air-conditioning system in high-grade buildings generally accounts for 40% to 60% of the total power consumption of the entire building. For the consideration of energy saving of air conditioning system, it is very important to design scientific and reasonable temperature controller and temperature control algorithm. In winter, the number of people using air conditioning is much higher than that using floor heating. However, under the same circumstances, the power consumption of geothermal floor heating is less than that of air conditioning. At present, or use air conditioning to undertake temperature regulation entirely, or air conditioning and floor warming are to undertake the job separately, dual-use temperature controller still did not use commonly on the market.

1 Function Description

At present, the temperature controller launched by E-TOP integrates air conditioning and floor heating temperature control, with a total of 5 working modes, including air conditioning cooling mode, air conditioning heating mode, floor heating mode, air conditioning combined heating mode and sleep mode. These five modes meet the needs of different seasons, while also considering a series of practical issues such as power consumption and power saving.

There are multiple electric routes between the central air conditioner and the temperature controller. For the convenience of installation and simple wiring, the connection between the temperature controller and the fan is cancelled, and 315 wireless communication is used to control the high, medium and low wind speed. We use a five-stop valve to control the flow of hot and cold water, by changing the size of the gear to achieve temperature control requirements. Dual-use temperature controller has a wide application prospect in hot spring clubs, hotels and other places.

2 Hardware Design

We design the relevant circuit for the main control chip based on HT67F489 chip of Hetai. This temperature controller is divided into two circuit boards, one is the power supply circuit board and the other is the temperature control panel. Among them, the main function of the power supply circuit board is to convert the voltage of 230V to 3.3V, and the voltage of 3.3V is used to power the temperature control panel. In the power supply circuit, we use LN5RO4D chip. LN5RO4D is a standard PwM controller integrated circuit, which can be easily applied to various low-power power adapters. It has few peripheral devices and a variety of internal protection circuits, which are simple. A transformer was used to convert 20V to 12V, followed by an AMS1117 high efficiency linear regulator, which stabilized the output voltage to 3.3V. The temperature control panel consists of the main control chip H67F489, code break screen, temperature sensor, 315 wireless communication module, etc., which is an important part of the function of the temperature controller. The main component of the temperature sensor is thermistor, the use of negative temperature coefficient thermistor, that is, the resistance value decreases when the temperature rises. The code breaking screen for the air conditioner and floor heating thermostat is specially customized. A total of 20 pins are designed to display 122 picture blocks, each picture block can be displayed separately, and the content displayed at the same time is simple and clear.

3 Software Design

The program is the soul of the thermostat, is an important basis for the thermostat to achieve various functions. Thermostat is the most important key procedure, namely press different keys to achieve the corresponding function, from left to right are the key mode of power supply selection key, timing open timing off trigger key, wind speed selection key, increment key, decrement key. The corresponding parameters and contents can be displayed on the screen only after the coding screen is programmed accordingly. The room temperature display is realized by AD conversion program. Through the timing program to achieve the function of timing on or off; Through 315 wireless communication program to control the wind speed of the fan; Through the serial port command to control the gear of the five-grade valve, so as to control the flow, to achieve the role of temperature regulation. Therefore, software design is very important in dual - use temperature controller

4 Energy consumption

In summer, directly choose air conditioning refrigeration mode, so that the indoor temperature reaches the set value, and ordinary central air conditioning has no difference. In winter, the combined heating mode of air conditioning and floor heating can be selected. When the indoor temperature reaches 25℃, the mode of floor heating can be changed at this time. On the one hand, the heating effect of air conditioning is fast and the heating effect of floor heating is slow. If you want to heat up quickly in a short time, the two modes can be realized at the same time. On the other hand, due to power consumption, the power consumption of air conditioning is greater than that of floor heating, so when the room temperature reaches human comfort, the air conditioning is immediately turned off. This kind of thermostat can accomplish this function very well. The comparison of energy consumption should be based on the same temperature regulation effect. In the case of the same temperature control, the energy consumption of floor heating is lower than that of air conditioning. At the same time, floor heating is in line with the human needs of "warm feet and cool top" in Traditional Chinese medicine, which will give people a comfortable feeling of warm feet and cool head. It is conducive to promoting human metabolism, improving blood circulation, and has a regulatory effect on cardiovascular diseases: it has prevention and treatment effects on arthritis, old cold legs and back pain in the elderly. The heat in floor heating process is mainly radiation heat transfer, indoor temperature distribution is more reasonable. Under the same comfortable conditions, the indoor setting temperature is 2℃ lower than that of the traditional convection heating indoor setting temperature, and the heat consumption can be saved by about 15%.