Solar water heating system design project

Transcription

1 Solar water heating system design project Project Description Solar technology makes use of the abundant energy in the sun, and it has little impact on our environment. Solar systems can be used in a wide range of products, from small consumer items to large commercial solar electric systems. Energy saving measures can play a significant role for lowering energy consumption and energy costs, as well as for environmental protection through the reduction of CO 2 emissions to the atmosphere that contributes to the greenhouse effect. One of the main building types with a great potential to apply measures of energy saving is the h o s p i t a l s [1]. The client, is King Abdulaziz university, who considers the use of the solar water heating system for King Abdulaziz university hospital. The solar water heating system will be used together with common boilers to heat water. Your task is the following: 1. Select the collector cell tilt angle ( fixed solar collector system or movable collector) 2. Solar water heating system size optimization ( the collector area will depend on the minimization of the total cost)

2 Design Procedure 1. Selection of the solar cells tilt angle based on the solar heating system location. The tilt angle must insure maximum possible incident radiation from the sun. You may design a movable solar water heating system to track the sun during the day. 2. Calculation of the hospital monthly heat load 3. Calculation of fraction of the monthly heating load supplied by the Solar Energy for different solar cells areas using the f-chart Method (see the useful relation) 4. System size optimization to minimize the total annual cost The parameter used for optimizing the system size "collector area" is the cost of heating makeup water from ambient temperature to cer tain higher temperature. Out of the total makeup water heating load L, the fraction 1- f is supplied by boiler. The cost of this boiler fuel is included in the estimation, in addition to the operating cost of the solar water heating system. Thus, Annual cost = annualized capital cost + boiler fuel cost + O peration & Maintenance cost + running cost From this annual cost of heating makeup water, the levelized cost is estimated. The O&M cost is taken as 2% of capital cost, while running cost is the cost of pu mping in solar water heating system. Deliverables Each team must communicate its final design to the client in both written and oral form. Your written team poster must contain a scaled orthographic sketch of the solar water heating system s y s t e m.

3 Useful relations Calculation of fraction of the monthly heating load supplied by the Solar Energy for different solar collector areas using the f- Chart Method The f-chart method is a correlation of the results of many hundreds of thermal performance s imulations of solar heating systems. The resulting simulations give f, the fraction of the monthly heating load (for space heating and hot water) supplied by solar energy as a function of two dimensionless parameters, X (Collector Loss) and Y (Collector Gain). X is related to the ratio of collector losses to heating loads, and Y is related to the ratio of absorbed solar radiation to the heating loads.

4 The F-Chart equations for the fraction f of the monthly space and water heating loads supplied by sol ar energy are the following. Example O n e-cover collectors are used for designing a solar heating system for Madison, Wisconsin (latitude 43 ). The values of F R (τα) n and F R U L were determined from standard collector tests as 0.74 and 4.00 W/m 2 C, respectively. The collector faces south and has a slope of 60 from the horizontal. In January, Madison has an average daily radiation of 11.9 MJ/m 2 on a 60 surface and an average ambient temperature of 7 C. The monthly heating load for both space and hot water in January is 36.0 GJ and F R / FR, the collector-heat exchanger correction factor, is The monthly average to normal incidence transmittance absorptance product is The collector loss, X, and collector gain, Y, and f for these conditions, with a collector area of 50 m 2 can be calculated as follows using the F-Chart method, resulting in the fraction of the annual heating load supplied by solar energy.

5 The annual mean solar radiation for all lands over the world is presented in Figure 1. Here it is obviously seen that the amount of incident solar radiation is different in each part of the world [2]. Fig. 1. Annual mean solar radiation in KWh/m 2 (Source: Intergovernmental Panel on Climate Change)

6 System functional diagram References 1. EPTA Ltd., GUIDELINES for ENERGY EFFICIENCY in HOSPITALS, Athens, Greece, Photovoltaic Systems Technology, Universität Kassel, Germany, Assessment Grading of the project will be carried out using the poster checklist and the E xcel soft copy.