Abstract: In view of the high cost of ground source heat pump drilling and the initial investment higher than that of ordinary heating and air conditioning, this paper uses the economic evaluation method to take the heating area of ​​10000m 2 in Harbin as the calculation object, and compares and analyzes the three driving sources of ground source heat pump (motor, gas , Diesel engines) and three kinds of auxiliary heat sources (electric boilers, oil boilers and gas boilers) for a total of 9 kinds of system combinations (initial investment, annual operating cost, annual total cost, net present value, net present value rate and investment Recovery period), analysis and calculation of the gas turbine-driven, 190kw auxiliary gas boiler ground source heat pump system is the best conclusion Keywords: Ground Source Heat Pump Heating and Cooling Technology Economic Ground Source Heat Pump is a ground using shallow ground heat Resources for heating, cooling new air conditioners. Because of its relatively high heat source temperature, stable throughout the year, does not change with the ambient temperature changes, so whether it is winter heating, or summer cooling, ground source heat pump COP are much higher than other heat source heat pump. At present, ground source heat pump has been widely used in many countries. Some cities in our country have set up ground-source heat pump demonstration projects, but there are still some difficulties in promotion. How do investors understand the economy of ground-source heat pumps? Therefore, the technical and economic analysis of ground-source heat pumps and comparison of various schemes Is necessary. In this paper, economic evaluation methods, the ground source heat pump several investment programs for technical and economic analysis. 1. Technical and economic evaluation methods and parameters Heating and cooling calculation of the main technical parameters are: heating load, air conditioning cooling load; economic parameters are: initial investment, annual operating costs, annual total cost, cash flow statement and its related parameters. 1.1 Main Economic Parameters 1.1.1 Initial investment refers to the sum of investments in various parts of ground source heat pump system: civil works costs, equipment purchase costs, installation costs and other expenses (including design fees, supervision fees and unforeseen expenses) Cost refers to the operating costs of various parts of the system, such as water, electricity, fuel costs; sewage charges; management staff salaries and management fees; equipment depreciation costs and equipment maintenance, overhaul and so on. 1.1.3 Annual Operating Costs refer to the deduction of equipment depreciation expenses from the total annual cost. 1.1.4 Cash flow statement Calculate the relevant economic parameters of investment projects using the cash flow statement method, such as financial internal rate of return, financial net present value, net present value rate and payback period of investment. (1) Net present value index: It refers to the present value algebra sum of the net cash flow discounted to the starting point of the net cash flow of each year by the investment project according to the benchmark return. The formula is: where X NPV is the net present value; A CI is the cash Inflow, refers to the heating or air conditioning sales revenue, recovery of residual value of fixed assets and recovery of liquidity; A CO for cash outflows, including fixed asset investment, liquidity, operating costs and sales tax people ic benchmark rate of return, this article take ic = 8%; n is the activity period of the project, record the construction period plus service life. (2) Net present value ratio: refers to the ratio of the NPV of the project to the present value of the total investment, that is, the NPV that the present value of the unit investment can bring. The formula is: where: X NPVR is the NPV of the project scenario; I p is the present value of the total investment in the project scenario; and I t is the investment in year t. According to the above definition, the project is feasible only when both the NPV and the NPV are greater than zero. In the multi-program choice, under the condition of sufficient funds, the program of large financial net present value first. However, due to different economic conditions, coupled with the size of the financial net present value can only indicate the total profit, did not reflect the impact of investment scale on the utilization rate of funds. Simply using the financial net present value of the largest criteria for program selection, often leads to the evaluator tend to choose a large investment, more profitable programs, while ignoring the less profitable, less investment, but better investment returns, so the net financial performance The value method is generally used in conjunction with the net present value method in order to explain what the net present value of the solution is obtained at. Under the condition of shortage of funds, the indicator of net present value ratio should generally be emphasized. (3) Investment payback period (including static and dynamic): It is the time needed to offset the total investment of the project by the net income of the project. Static is not considered the time value of money, and the dynamic is to consider the time value of money. Let PI be the static investment payback period, the calculation formula is set PI 'as the dynamic payback period, the calculation formula is 1.2 Calculate the given parameters 1.2.1 Weather parameters The indoor heating design temperature is 20 ℃, indoor cooling design temperature is 27 ℃, Heating, cooling outdoor calculation of temperature with reference to the actual average daily temperature in 2000 in Harbin, the number of heating days 180d, the number of cooling days 60d, day heating 18h calculation, and then comparative analysis; daily cooling hours to the actual needs of the cooling Hours calculated. 1.2.2 Calculation object Select the residential building as the calculation object, the maximum heating load for heating is 70W / m 2 and the heating area is 10,000m 2; the maximum cooling load of air conditioner is 70W / m 2 L5J; Calculate. Ground source heat pump system 1.2.3 ground source heat pump dual-use, both heating and cooling. A total of three kinds of driving sources were: motor, diesel engine, gas engine; auxiliary heat sources were: electric boilers, oil boilers, gas boilers. Waste heat from diesel or gas engines is recovered when the drive source is a diesel or gas engine. Ground source heat pump heating and heating coefficient to take 3.1, cooling and cooling factors to take 4.0, single air conditioning and cooling coefficient to take 2.9; thermal efficiency of electric boilers to take 1.0, oil boiler and gas boiler thermal efficiency 0.85; diesel and gas engine waste heat recovery Take 0.60. Ground source heat pump buried underground pipe using vertical casing, hole depth 100m, buried pipe using high density polyethylene (HDPE) pipe, per unit length of the hole heat transfer take 35W / m2. Ground source heat pump life of 15a, the total system heating capacity of 700kW.
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