In hot water projects, the best energy-saving plan may not be completed independently by a heat source system. Under specific conditions, the best plan may be in the form of "multi energy combination".
The 100 ton hot water project of X hospital is a good case. Through the detailed operation comparison of the construction party, the project adopts the multi energy combination system of "air source heat pump + solar energy", which can save 503500 yuan / year compared with the solar energy system and 291500 yuan / year compared with the air source heat pump system.
Project: hospital daily water consumption 100 tons
X hospital has 7 buildings in total, including outpatient building, science and technology building, infectious disease building, logistics support building and inpatient building, including 3 inpatient buildings with more than 400 beds. The project system provides hot water demand for the whole hospital, with hot water consumption of about 100 tons, local commercial power consumption of about 1.1 yuan / kWh and gas cost of about 3.7 yuan / m3.
The annual average sunshine hours is 2028 hours, and the annual accumulated temperature is 6829.3 °C. It belongs to the general area of class III solar energy resources, which is the middle class area of solar thermal energy resources and has good solar energy utilization conditions.
The average temperature is 18.4 °C, the average relative humidity is 75%, the annual average rainfall is 1187.8mm, and the annual rainfall is about 2.8 billion cubic meters. The average frost free period is 309 days. The first frost appears in the beginning of December and the last frost appears in the end of January. The climate conditions are very suitable for the operation of air source heat pump.
Comparison: operation cost analysis of different heat sources
No matter what kind of heat source equipment (gas boiler, solar energy, air source heat pump) is used, the hot water circulating device is essential. Therefore, the power consumption of necessary supporting equipment such as circulating water pump is not reflected in this comparison, only the operation cost of heat source equipment is compared.
According to the calculation of 100 tons of water, 15 °C water in, 55 °C water out and 40 °C temperature difference, the required heat is: Q = cm (T1-T2) = 100 × 1000 × 55-15 = 4000000 kcal.