Economic benefit comparison

Thread Content

Economic efficiency comparison (calculated based on the energy required to raise 20 tons of water from 10°C to 45°C per day): I. Total energy: The system consumes a total of 3×106 kJ of energy each day to raise 20 tons of water at 10°C to 45°C. The calculation is as follows: Q = CpmΔT = 4.18 × 20 × 10³ × (45 – 10) = 3 × 10⁶ kJ. Where: Q is the energy required for the operation of this hot water system (in kJ); Cp is the specific heat capacity of water (Cp = 4.18 KJ/kg•°C); ΔT is the temperature increase of the water (i.e., the difference between the temperature of the hot water and the temperature of the water at baseline); m is the mass of water (in kg). II. Economic comparison of different hot water boiler systems using solar energy, fuel oil, gas, electricity, and coal 1. The equivalent calorific values of various fuels are as follows: Fuel oil: 41310 kJ/kg ； Natural gas: 35530 kJ/Nm3 ； Electricity: 3600 kJ/Kwh ； Industrial coal: 20,900 kJ/kg. 2. The boiler efficiencies and energy costs are shown in the table below, Table 1. Category: Coal-fired boilers, Fuel-fired boilers, Gas-fired boilers, Electric boilers; Efficiency: 50%, 80%, 85%, 95%; Energy costs: Coal: 0.70 yuan/kg, Diesel: 5.0 yuan/kg, City gas: 2.50 yuan/m3, 0.60 yuan/KWh. The energy costs listed in Table 1 represent the current average national prices; when making calculations, it is necessary to take into account the natural increase in energy costs, using a 10-year cycle with an average annual growth rate of 5%. The resulting values are as follows: Fuel: 6.08 yuan/kg ； Natural gas: 3.04 yuan/Nm3 ； Electricity: 0.73 yuan/Kwh ； Industrial coal: 0.85 yuan/kg. 3. The costs for various energy sources are calculated as follows (over a period of 15 years): a) If all the required heat is generated by fuel boilers, the daily fuel consumption is: 3×10^6 kJ / (41310×80%) = 90.8 kg. The daily cost of fuel is: 90.8 kg × 6.08 yuan/kg = 552.06 yuan. The annual fuel cost is 552.06 × 365 = 201,503.36 yuan. The total fuel cost over 15 years is: 201,503.36 × 15 = 3,022,550 yuan. b) If all the required heat is generated by gas boilers, the daily gas consumption is: 3×10^6 kJ / (35530×85%) = 99.34 m³. The daily cost of gas is: 99.34 × 3.04 yuan/Nm³ = 302 yuan. The annual gas cost is 302 × 365 = 110,230 yuan. The total gas cost over 15 years is: 110,230 × 15 = 1,653,450 yuan. c) If all the required heat is generated by electricity, the daily electricity consumption is: 3×10^6 kJ / (3600×95%) = 877.19 kWh. The daily electricity cost is: 877.19 × 0.73 yuan = 640.35 yuan. The annual electricity cost is 640.35 × 365 = 233,727.75 yuan. The total electricity cost over 15 years is: 233,727.75 × 15 = 3,505,916 yuan. d) If all the required heat is generated by coal boilers, the daily coal consumption is: 3×10^6 kJ / (20900×50%) = 287.08 kg. The daily cost of coal is: 287.08 × 0.85 yuan/kg = 244 yuan. The annual coal cost is 244 × 365 = 89,060 yuan. The total coal cost over 15 years is: 89,060 × 15 = 1,335,900 yuan. e) Costs related to solar water heating systems and alternative energy sources: (1) Investment in solar system equipment: 500,000 yuan. (2) Other costs related to alternative energy sources, together with the investment in solar system equipment: Assuming 60 rainy days per year during which other energy sources must be used, the annual energy costs for the solar water heating system vary depending on the type of alternative energy used. If oil is used as an alternative energy source, the total annual fuel cost for those 60 days is: 552.06 yuan × 60 = 33,123 yuan. The total cost over 15 years is 496,845 yuan ； The total cost of investing in solar system equipment and related expenses is: 496,845 yuan + 500,000 yuan = 996,845 yuan. If gas is used as an auxiliary energy source, the annual cost for 60 days of use is: 302 yuan × 60 = 18,120 yuan. The total cost over 15 years amounts to 271,800 yuan ； The total cost of investing in solar system equipment and related expenses is: 271,800 yuan + 500,000 yuan = 771,800 yuan. If electricity is used as an auxiliary energy source, the total annual electricity cost for 60 days is: 640.35 yuan × 60 = 38,421 yuan. The total cost over 15 years amounts to 576,315 yuan ； The total cost of investing in solar system equipment and related expenses is: 576,315 yuan + 500,000 yuan = 1,076,315 yuan. If coal is used as an auxiliary energy source, the annual coal consumption cost for 60 days per year is: 244 yuan × 60 = 14,640 yuan. The total cost over 15 years amounts to 219,600 yuan ； The total cost of investing in solar system equipment, including both components, amounts to: 219,600 yuan + 500,000 yuan = 719,600 yuan. Based on the above calculations, the investment benefits of solar energy compared to various conventional energy boiler systems are shown in Table 2. This table provides a comparison of the total costs over 15 years for different systems. For solar energy systems using fuel, the total cost is 996,845 yuan with a payback period of 4.9 years; for fuel boiler systems, it is 3,022,550 yuan. For solar energy systems using gas, the total cost is 771,800 yuan with a payback period of 7 years, while gas boiler systems have a total cost of 1,653,450 yuan. Solar energy systems using electricity have a total cost of 1,076,315 yuan with a payback period of 4.6 years, whereas electric boiler systems have a total cost of 3,505,916 yuan. For solar energy systems using coal, the total cost is 719,600 yuan with a payback period of 8 years, while coal boiler systems have a total cost of 1,335,900 yuan. Table 3 shows further details on the investment benefits of solar energy compared to various conventional energy boiler systems. Note that the figures above are based on ideal conditions; taking coal as an example, issues such as adulteration and weight reduction are not taken into account, and these problems can significantly affect the efficiency and economic viability of coal use ； Project: Solar energy system, fuel boiler, gas boiler, coal boiler, electric boiler, heat pump system. Energy is required daily to raise 20 tons of water from 10°C to 45°C; the amount of energy needed is 3×10^6 kJ.
Equipment investment (yuan): 500,000, 40,000, 30,000, 45,000, 50,000, 200,000.
Equipment service life (years): 15, 55, 55, 55, 15 years.
Total equipment investment (yuan): 500,000, 120,000, 90,000, 135,000, 150,000, 600,000.
Number of days of use per year: 30, 53, 65, 365, 365, 365, 365.
Fuel price (including inflation factors): Taking electric assistance as an example, 0.73 yuan/KWh, 6.1 yuan/kg, 3 yuan/Nm³, 0.85 yuan/kg, 0.73 yuan/KWh, 0.36 yuan/KWh.
Daily fuel cost (yuan): 640.35 for 60 days with electric assistance; 552.06, 3022.44, 640.35, 320.17.
Annual fuel cost (yuan): 38,421 (for 60 days); 20,150, 3.361, 110,230, 890,602, 337,281, 168,641.
Fuel cost over 15 years (yuan): 576,315, 302,255, 016,534, 501,335, 900,350, 591,617, 529,581.
Labor costs over 15 years: 150,000, 150,000, 225,000, 75,000, 50,000.
Annual costs for maintenance, waste disposal, and fuel transportation (yuan): 600, 600, 0600, 18,000, 600, 500.
Costs for maintenance, waste disposal, and fuel transportation over 15 years (yuan): 9,000, 90,000, 90,000, 270,000, 90,000, 7,500.
Boiler room cost: 10,000, 10,000, 10,000, 10,000, 5,000.
Total cost of equipment and operation over 15 years (10,000 yuan): 108.53, 39.31, 91.21, 97.63, 752, 41.5.
Comparison with solar energy: Payback period (years): 4.78, 7.6, 4.3, 6.7.
Types of energy or fuel: Solar energy, diesel, natural gas, industrial coal, electricity.
Status of energy sources: Abundant and inexhaustible; increasingly scarce globally.
Trend in fuel prices: Free use; continuously rising prices.
Charges for capacity expansion: None, yes, yes, no, yes.
Environmental aspects: Environmentally friendly, no pollution; severe pollution, very severe pollution; serious indirect pollution.
Noise levels: Very low noise; high noise and vibration; low vibration and noise; high vibration and noise; very low noise.
Safety aspects: Very dangerous, very dangerous, very dangerous, dangerous, safe.
Overall social benefits: Very good, average, poor, fairly good, good