Views:3 Author:Site Editor Publish Time: 2020-04-13 Origin:Site
1. Runner full heat exchanger
The surface of the runner heat exchanger is honeycomb, coated with a layer of adsorbent material as a desiccant. Place the runner between the air ducts to divide it into two parts. The exhaust air from the air-conditioned room is discharged from one side, and outdoor air enters from the other side in the opposite direction. In order to increase the heat exchange area, the wheels rotate slowly (10 ~ 12 rpm). Half of the wheels absorb stored heat from the hotter air, and when rotated to the other side, the heat is released and the heat is transferred. The desiccant attached to the surface condenses the moisture from the high-humidity air stream, absorbs it through the desiccant, and rotates to the other side, releasing the moisture into the low-humidity air stream. This process transfers latent heat.
Separator plates are provided on both sides of the rotating body of the heat exchanger to make the fresh air and the exhaust air flow in the opposite direction. The runner chip is made of special paper or aluminum foil, and its surface is coated with a hygroscopic coating to form a carrier for heat and moisture exchange. It rotates at a speed of 10-12r / min, first collecting the cold and heat in the exhaust air In the heat storage body (rotor core), it is then transferred to the fresh air. The air passes through the heat storage body at a flow rate of 2.5-3.5m / s. The heat and moisture exchange is performed by the temperature difference between the fresh air and the exhaust air and the difference in steam partial pressure. Therefore, both sensible heat and latent heat can be recovered.
2. Low temperature heat pipe heat exchanger
In 1942, American engineers proposed the principle of heat pipes. In the early 1960s, research and trial production began. It was first used in spacecraft and nuclear reactors. In the 1970s, heat pipe heat exchangers were eventually used as heat energy recovery devices in new wind systems In the HVAC industry, it shows excellent superiority. The heat pipe is a heat transfer element that realizes heat transfer by the phase change of its internal liquid.
It has the following characteristics:
(1) Each heat pipe is permanently sealed, there is no additional energy loss during heat transfer, no running parts, and operation reliability high.
(2) The structure of the heat pipe heat exchanger determines that it is a typical countercurrent heat exchange, and the heat pipe is almost isothermal operation, so the heat pipe heat exchanger has high efficiency.
(3) Due to the heat exchange of hot and cold gas, the heat receiving area is easily expanded on the outer surface of the heat pipe.
(4) The hot and cold gases are separated by a partition, there is no leakage, so there is no cross contamination problem.
(5) Due to the wide fluid flow channel, the resistance loss is small.
(6) Each heat pipe is completely independent and easy to maintain.
(7) From the perspective of environmental adaptability, waste heat recovery efficiency, pressure loss, blockage prevention, cleaning, life and other comprehensive indicators, heat pipe heat exchangers have the advantage.
The heat pipe is composed of a tube shell, a liquid-absorbing core and an end cap. The tube is evacuated and filled with appropriate working fluid, and then the two ends are sealed. The heat pipe is both an evaporator and a condenser. One end of the heat flow absorbs heat is the evaporation section. The working medium absorbs the heat and then evaporates and vaporizes. It flows to the other end, the condensation section, releases heat and liquefies, and flows back to the evaporation section by capillary force to complete the cycle automatically.
The heat pipe heat exchanger is assembled by a single heat pipe, the evaporation section and the condensation section are separated by a partition in the middle, and the heat pipe heat exchanger completes the heat transfer by the phase change of the working medium in the heat pipe. Each heat pipe is an unpowered refrigeration cycle system. The heat transfer rate is thousands to tens of thousands of times of the same metal. The temperature difference of 0.1 ℃ is the thermal response. It was originally used on artificial satellites to solve the sun and shade. Uneven heating is one of the necessary equipment on the artificial satellite. Now, it is more and more widely used in the field of air conditioning and waste heat recovery. An expert from Waseda University in Japan said: "Japan pays special attention to energy conservation and environmental protection, and heat pipe technology has found a way for energy conservation and environmental protection due to its efficient heat transfer new road". The heat pipe heat exchanger is introduced and selected in the HVAC design manual.