Among the greenhouse heating methods, there are not many countries that use the heating method using electricity. In fact, heating using electricity is not very reasonable to produce electricity by thermal power generation using fossil raw materials to produce electricity. In terms of the final efficiency, it is less than 40% considering the boiler efficiency, power generation efficiency, and energy use required to operate power generation facilities. However, when considering the loss incurred in going through the transmission and substation facilities to the final consumer, and the installation and maintenance cost of the facility, it is less than 35%. This can be said to be inefficient when considering that the efficiency is 85% when installing an oil boiler in a greenhouse and heating it. However, as the production rate of electric energy by direct production methods using natural energy such as hydropower 90%, solar power 20%, wind power 30%, etc. is gradually increasing, the heating method using electricity is not so pessimistic.
Greenhouse heating methods using electricity can be broadly divided into electric boilers and electric heaters. Electric boilers use electric heaters to heat water and heat exchangers installed in the greenhouse. This method was initially used by many farms, but now Very few farms use it. In this method, the water in the heat storage tank and hot water pipe must be heated and stored at a certain temperature or higher even during the day when sunlight is abundant, and a large amount of electrical energy is consumed at this time. This requires several hours of preheating time to raise the temperature to about 70℃, which is the required temperature for heating, when the temperature of the water in the pipe and heat storage tank is low to room temperature when heating is required due to the fluctuating weather and night temperature drop in winter. In addition, the lifespan of the heater installed inside the electric boiler is 2-3 years, so it is inefficient due to the replacement and maintenance cost and the heat loss from the piping inside and outside the greenhouse of the heat storage tank with excessive initial electricity receiving capacity. A brine boiler that heats brine using a similar principle was initially produced by a few companies, but now they have all disappeared. This is a method of supplying water and heat exchange inside the greenhouse by heating the oily liquid with a high boiling point to a high temperature instead of water.
Electric hot air blowers can be divided into the method of directly exchanging heat from the heater with air using a blower fan, and the indirect heating method of heating water using a heater and heat-exchanging water with circulating air in a heat exchange coil. As for how to do this, the heater that heats water does not have a long lifespan due to its structure, so it needs to be replaced. Periodic water replenishment is required due to natural evaporation while the heater is in operation, and there is a risk of freezing when not operating in winter. These indirect heating type hot air heaters are expensive compared to their capacity and have a short lifespan, so the number of farms that use them is limited.
The direct heating type hot air heater is a heater blower fan motor control device with a simple structure, so it is inexpensive, easy to use, has no malfunctions, has a low maintenance cost, and has a long lifespan. In the early days of electric heating, some companies produced large heaters such as 100kw and 120kw, which were designed based on the model of the initial oil heater, and only the energy source was changed from oil to electricity, and the heater was made and supplied with a slight structural change. There are many problems to use on farms, such as being large and heavy and inconvenient to move. On the other hand, the small size 10kw 12kw 15kw heater is light and easy to move and install, so it is the most popular hot air heater used in many farms today. Depending on the function and integrated control function, various installation methods are possible depending on the type of farm structure cultivated, such as a stationary type or a floor-standing type depending on the installation type.
The importance of greenhouse heating
The importance of greenhouse heating
Energy saving technology
Energy saving technology
Types and advantages and disadvantages
of greenhouse heating equipment
Types and advantages and disadvantages
of greenhouse heating equipment
