Overview of central air conditioning billing

The operating cost of central air-conditioning billing system plays a key role in selecting air-conditioning schemes and formulating property fees. Usually, design researchers and developers simply calculate the operating cost of central air conditioning refrigeration according to the difference of electricity charges between winter and summer. Due to the lack of careful analysis and consideration of investment, operation and maintenance costs, the calculated structure can not fully reflect the actual operation costs.

The operating cost of Apotheker central air conditioning system includes three parts: direct energy consumption, maintenance cost and investment cost sharing.

1. 1 direct energy consumption

Direct energy consumption includes direct water and electricity costs of refrigeration and cooling supply in refrigeration station. Because the terminal equipment is powered by the power system of each floor, it has been included in the user's electricity bill and will not be repeated in air conditioning. The related equipment of the freezing station includes water chillers, freezing cooling water pumps, cooling towers, etc.

Because the efficiency of refrigerators is different under different loads, strictly speaking, the calculation of power consumption should be real-time. Usually, in the scheme calculation, the annual operating electricity fee can be obtained by multiplying the cooling capacity (cooling ton hours) by the cooling efficiency (COP) of the system. It should be emphasized that the system efficiency here is not the EER value of water chillers, and the power consumption of cooling towers and pumps must be considered. Generally speaking, for the system with centrifugal water chillers, the comprehensive efficiency of the cooling system is 1.005km/KTH, that is, the cooling load of 1 cold ton hour requires 1.005 kWh of power consumption.

The direct water fee for operation is mainly a supplement to the cooling water system, which supplements the evaporation consumption of cooling tower water. The circulating capacity of general cooling water system is 0.907m3 /RTH, and the water replenishment parameter is 2%, so the operating water fee is 0.0 18 148m3 /RTH and 4.8gal/RTH.

1.2 Maintenance cost

The maintenance cost of central air conditioning system includes many items, mainly including:

① Labor cost

Central air conditioning refrigeration needs to be equipped with fixed operators and simple maintenance personnel, but also responsible for the maintenance and basic maintenance of the end system of each floor. For the production capacity of 1000RT, it is necessary to equip 1 supervisor and 4 skilled workers, and the total annual salary after tax is about 200,000 yuan.

② Maintenance cost

There are usually two ways to maintain the central air-conditioning system, that is, to entrust a professional company to maintain it and to maintain it by itself. Compared with the total life cycle cost, the professional maintenance of the former is more economical. Maintenance contracts include pipeline cleaning, electrical inspection and mechanical maintenance. Usually, the annual contract amount of 1 cold ton is 2 million.

1.3 cooling water treatment and cooling tower maintenance

Because most domestic projects use imported original components of water chillers and pumps, the maintenance amount is less, while cooling towers are usually domestic equipment. In addition, the climate and environmental conditions are complex, and the maintenance amount of cooling tower is obvious, which needs to be considered separately in the summary of operating expenses, mainly the dosing treatment of cooling water and the replacement of vulnerable parts of cooling tower. The usual cost index is 30 yuan per cold ton per year.

1.4 refrigeration system supplement

The refrigerant leakage of water chillers varies with model and service life. Taking the Second Hospital of Centrifuge Unit as an example, the annual leakage per cold ton is about 2-8 kg, and the conversion result is that the cost of replenishing refrigerant per cold ton per year is 67 yuan.