What are the heating methods of the greenhouse?
1. Boiler heating
Hot water heating consists of boilers, hot water transmission pipelines, circulating water pumps, radiators and various control and regulating valves. The heat medium used in the hot water boiler can be coal, gas, and oil. The water is heated by fuel combustion, and the indoor temperature is raised through the hot water delivery pipe. The denser the pipe arrangement, the more uniform the indoor temperature.
Boiler heating has a large one-time investment; the cycle power is large; the storage time of water for heat is relatively long, the heat loss is small when using hot water to warm up, and the temperature fluctuation in the greenhouse is relatively small; the operating cost is relatively economical.
It is recommended to use in greenhouses where the outdoor design temperature is below -10°C in winter or where the heating time is more than three months.
2. Steam heating
Steam heating, as the name implies, is steam, which is conveyed by steam for heating. The steam temperature is generally 100-110°C, so the transmission pipeline and radiator must be resistant to high temperature, high pressure, corrosion resistance and good sealing. The steam heating method has high temperature and high pressure, but has a smaller heat dissipation area than hot water heating; low one-time investment; and stricter management requirements.
It is more recommended to choose when there are steam resources or a large area of contiguous greenhouses for heating.
3. Hot air heating
Hot air heating is a direct heating method, and the air heated by a heat exchanger is directly sent into the greenhouse.
There are two ways of hot air heating:
Hot air blower (hot water or steam passes through the heat exchanger, after the heat exchange, the blower blows the hot air directly into the room), and hot air stove (heating furnace directly burns or heats air). Hot air blowers are divided into electric hot air blowers, hot water hot air blowers and steam hot air blowers. Hot blast stoves are classified into coal-fired hot blast stoves, oil-fired hot blast stoves and gas-fired hot blast stoves according to the heat medium.
The method of conveying hot air: using pipeline transportation (uniform air outlets are provided on the conveying pipeline, and the room temperature is relatively uniform. The pipeline material can be plastic film or canvas tube. It can be arranged in the air or under the cultivation bed) and without pipeline transportation.
The hot blast stove is forced to heat the air without the loss of starting the boiler, so the general heating efficiency is high; the hot blast stove starts fast and can heat up quickly. When the temperature difference is small, it can be closed and opened at any time to adjust the temperature; but the temperature rise is uneven , The temperature fluctuation is relatively large; the heat duration is short.