Thermal Economic Analysis and Evaluation of Fan Coil Units Thermal economic analysis is to convert the actual energy consumption of a thermal system into cash through a cash balance relationship and a balanced relationship. If the annual energy consumption is used as the calculation basis, the balance equation of the fan coil unit is: Ew1+N=Ew2+EQ+E, Ew1, Ew2 respectively represent the cold water inlet and outlet of the fan coil unit, kJ/a; N is The power consumption of the fan, kJ/a; EQ is the output cooling capacity of the fan coil unit, kJ/a; E indicates the loss due to heat transfer temperature difference and resistance loss, etc., kJ/a. 焓 consists of two parts: cooling capacity EwQ and mechanical Ew,m. The cooling capacity and the mechanical quantity can be further expressed as: EwQ=mw21cpT0Tw-1dT=T0Twm-1Qw(4)Ew, m=mw12Vdp=mwVwm(p1-p2)=mwVwmpw=Vpw where Q0 is the annual supply of the fan coil unit Cooling capacity, kJ/a; Tam is the average air temperature of the inlet and outlet of the fan coil unit, K; Qw is the annual heat absorption of cold water, kJ/a; mw is the annual mass flow of cold water, kg/a; Twm is the average temperature of cold water, K; Vwm is the average specific volume of cold water, m3/kg; pw is the pressure drop caused by flow resistance of cold water, kPa; V is the annual volume flow of cold water, m3/a. It can be seen from the above analysis that the second law of thermodynamics is utilized. The analysis method can divide the energy input into the cold water into two parts, and the first part is equivalent to the minimum amount of work consumed to obtain the cooling quantity Qw, and the second part of the mechanical enthalpy is the mechanical energy of the pump consumed to overcome the water resistance. This is not reflected in the energy analysis method of the first law of thermodynamics. According to the principle of thermal economics, the cost equation of the fan coil unit is: cQEQ=cw(Ew1-Ew2)+cNN+cnZ where cQ represents the output unit price of cold, yuan/kJ; cw represents the unit price of cold water, yuan/kJ; cN represents the unit price of power consumption, yuan / kJ; Z represents the initial investment cost of the fan coil unit, yuan; cn represents the annual depreciation rate of the initial investment fee, 1 / a. cQT0Tam-1Q0=cwT0Twm-1Qw+Vpw+cNN+cnZ further analysis found that the mechanical loss in the cold water enthalpy is actually the amount of work of the cold water pump to overcome the water resistance, and the cold content is equal to the consumption of the refrigerator. The minimum power consumption, these two values ​​have the same properties as the power consumption of the fan, and the cost unit price can be the same, that is: cw=cN, so the fan coil unit output cooling unit price: cQ=cNT0Twm-1Qw+ Vpw+N+cnZT0Tam-1Q0=cNex+cnZT0Tam-1Q0 where ex=T0Tam-1Q0T0Twm-1Qw+Vpw+N is the efficiency of the fan coil unit. The unit price of the cooling capacity of the fan coil unit is composed of two parts: energy consumption cost and equipment depreciation expense. When the ambient temperature T0 and the operating parameters Tam and Twm are constant, the energy consumption cost decreases with the increase of the unit power cooling capacity, and increases with the increase of the water resistance loss pw; the equipment depreciation fee is the initial investment and the year. Depreciation rate (including annual interest rate and service life), annual operating time and other factors. The unit price of the cooling capacity of the fan coil unit is a comprehensive technical and economic evaluation index, which can be used as the basis for the selection and optimization design of the fan coil unit. The calculation example takes Jinan as an example. The values ​​are: T0=307.8K, Twm=282.5K, Tam=294K, cN=0.7 yuan/(kWh), i=6.63%, n=10a,=2880h/a, Z= 144.7+164.2F (yuan). The research and analysis of the fan coil unit shows that the energy consumption (mainly the energy consumption of the fan) is the key factor affecting the unit price of the cooling cost. The fan coil unit is still a low-cost product. Appropriately increasing the heat transfer area of ​​the air cooler (ie increasing the length of the string) is a feasible method to reduce the energy consumption and thus the unit price of the cooling cost. Woven Fabric,Spun Rayon Fabric,Rayon Challis Fabric,Solid Rayon Fabric Shaoxing MingFang Textile Co., Ltd , https://www.printings-fabric.com