Solar Thermal

Running Head: SOLAR ENERGY
Solar Water Heaters
[Name of the Writer]
[Name of the Institution]

Table of Contents
TOC o “1-3” h z u Introduction PAGEREF _Toc468741353 h 2A) Solar Thermal Collectors PAGEREF _Toc468741354 h 3A-1) Instantaneous Efficiency PAGEREF _Toc468741355 h 3A-2) Linear Regression Analysis PAGEREF _Toc468741356 h 12B) Suitability for Installation of Solar Water Heater PAGEREF _Toc468741357 h 13B-1) Suitability of the Roof PAGEREF _Toc468741358 h 14B-2) Weather and Climatic Conditions PAGEREF _Toc468741359 h 15C) Estimation of Hot Water Consumption PAGEREF _Toc468741360 h 19C-1) Family Consumption of Hot Water Per Year PAGEREF _Toc468741361 h 20C-2) Shower, Bath and Basin Hot Water Consumption PAGEREF _Toc468741362 h 20D) Energy Content Calculation of Conventional Water Heater PAGEREF _Toc468741363 h 21E) Heat Extracted from Solar Water Heater and Financial Outlooks PAGEREF _Toc468741364 h 22Conclusion PAGEREF _Toc468741365 h 24

List of Figures
TOC h z c “Figure” Figure 1: Flat Plate Collector Pictorial View (Kalogirou, 2004, p. 241). PAGEREF _Toc468741414 h 6Figure 2: Evacuated Tube Collector (Kalogiru, 2004, p. 246). PAGEREF _Toc468741415 h 9Figure 3: Geographical Location of Portside, Nottingham (Google Maps Source). PAGEREF _Toc468741416 h 15Figure 4: Aerial View of the Apartment (Google Maps Source). PAGEREF _Toc468741417 h 16Figure 5: Average Maximum and Minimum Temperatures in Nottingham, UK (Meteoblue, 2016). PAGEREF _Toc468741418 h 17Figure 6: Cloud Condition and Precipitation in Nottingham, UK (Meteoblue, 2016).

PAGEREF _Toc468741419 h 18Figure 7: Maximum Temperature Profiles in Nottingham, UK (Meteoblue, 2016). PAGEREF _Toc468741420 h 19Figure 8: Amount of Precipitation in Nottingham, UK (Meteoblue, 2016, n.d.). PAGEREF _Toc468741421 h 20
List of Charts
TOC h z c “Chart” Chart 1: FPSWH Instantaneous Efficiency PAGEREF _Toc468741426 h 8Chart 2: ETSWH Instantaneous Efficiency PAGEREF _Toc468741427 h 10Chart 3: CETSWH Instantaneous Efficiency PAGEREF _Toc468741428 h 12Chart 4: FPSWH, ETSWH and CETSWH Instantaneous Efficiency Comparison Scatter Plot PAGEREF _Toc468741429 h 13Chart 5: Linear Regression Comparison of FPSWH, ETSWH and CETSWH PAGEREF _Toc468741430 h 14
List of Tables
TOC h z c “Table” Table 1: Instantaneous Efficiency Calculation of FPSWH PAGEREF _Toc469271358 h 7Table 2: Instantaneous Efficiency Calculation of ETSWH PAGEREF _Toc469271359 h 9Table 3: Instantaneous Efficiency Calculation of CETSWH PAGEREF _Toc469271360 h 12Table 4: FPSWH, ETSWH and CETSWH Slope and Intercept Values PAGEREF _Toc469271361 h 15Table 5: Heat Extraction Calculation from FPSWH PAGEREF _Toc469271362 h 26

Solar Water Heaters
IntroductionSun is a sphere having a diameter of around 1.39×109 m and it can contribute towards one of the most commonly used renewable energy source. The core advantage that can be attained from solar energy is that it is clean having a potential of providing energy needs without any detrimental impact to the environment. Fossil fuels have always outranked renewable energy resources because of their relatively economical nature with massive profit opportunities. However, the environmental impacts and subsequent regulation that includes CO2 costs have led towards the development of harvesting techniques for renewable energy.
The solar heating system is one of the most widely used renewable energy alternative quite commonly used all across the globe. The solar thermal heating system facilitates the usage of household water and swimming pool heating outlooks. The system is mainly used for collection of heat from the Sun and thereby utilizing the energy to transfer heat to the air or any other fluid which in turns allows transfer of heat to directly or indirectly heat water. The system also provides cost effective alternatives as compared to conventional water heating means on the long-term basis. The fixed cost incurred by solar water heater is quite higher as compared to the conventional water heating systems. It is because of the fuel (sunlight) can be available on a long-term basis. In order to harvest the sunlight energy, the solar heating and collection system requires unshaded or unblocked area on the roof. Most importantly, the choice of system is highly dependent on the collectors’ type together with geographical location, climatic conditions and the usage of solar water heating system (National Renewable Energy Laboratory, 2016, pp. 6-11).
The main component of solar water heater is the solar collectors. In homes having swimming pools, a storage tank for solar heated water is also maintained in order to have a steady supply of water downstream. Apart from that, the systems are widely categorized into two categories; namely, active and passive solar water heating systems. Active systems are quite commonly used with a water circulating pump along with process control measures. However, passive systems are equipped without the incorporation of circulation pumps.
A) Solar Thermal Collectors Solar energy collectors are quite similar to heat exchangers and have the capability to transfer radiation heat from sunlight towards the internal energy depending on energy transfer mechanism. The major part of the solar thermal system is solar collectors. This component is mainly used for absorption of incoming radiation from sunlight and converting it into heat and thereby transferring the heat to the working fluid (Mills, 2004, p. 21). The working fluid in most thermal collectors can be water or air depending on the application. The solar energy that is collected from the solar thermal collectors is then carried from circulating fluid towards the hot water. It can also be circulated in a thermal storage tank that can be used to store and reuse a significant amount of energy for utilization during the evening, night and on cloudy days. Solar thermal collectors are mainly categorized in two broader divisions; namely, stationary and concentrating (Tian and Zhao, 2013, pp. 540-541).
Solar collectors are quite commonly distinguished based on their motion. It implies that it depends on its characteristics; like, single axis, stationary, and dual axes tracking along with the operating temperature as well. Stationary solar collectors are fixed on a specified position without any motion and hence, it does not have the capability to track sunlight. Stationary collectors are of three basic types. It includes FPC (Flat Plate Collectors), CPC (Stationary Compound Parabolic Collectors) and ETC (Evacuated Tube Collectors).
A-1) Instantaneous Efficiency
For calculations involving instantaneous efficiency of Fixed Plate Solar Water Heater (FPSWH), Evacuated Tube Solar Water Heater (ETSWH) and Concentrating Evacuated Tube Solar Water Heater (CWTSWH), it should be noted that it is necessary for making data presentable for designing a solar panel system. During the mid of the 1970s, some new collector designs have surfaced thereby requiring a standardized procedure to be devised by ASHRAE. The standard ASHRAE 93-2003 are quite usually used for calculations involving the collectors’ thermal efficiency calculations. It can be considered in three major parts; namely, instantaneous efficiency, solar energy’s angle of incidence and subsequently, time constant for collector (Kalogirou, 2004, pp. 235-239).. The scope of the assignment only comprises of instantaneous efficiency of above mentioned solar water heaters.
The most rudimentary method is to expose the operating collector towards the solar radiation and thereby measure the performance of thermal collector. The useful gain can be calculated as:
Qu= mCp(To-Ti) (Struckmann,2008, pp. 1-3) Besides that, the factors of wind velocity, ambient temperature, and radiation absorption on collector plate are some of the most important factors. Hence, in this regard, two types of information are quite important that includes thermal output data and collector parameters. The prior determines the thermal performance while the later indicates the absorption of energy by collectors and the energy loss to the environment.
ASHRAE 93-2003 standard has formulated some standard testing procedures pertaining to air heaters and liquid heaters. The details for the different types of collectors vary; however, the procedure remains the same. It includes facilitation of collector with a fluid inlet source to be maintained at maintained inlet temperature. However, tests are conducted based on some ranges of different inlet temperatures. Solar radiation (isolation) values are measured through pyranometer placed on the collector’s surface. Apart from that, facilities and equipment are provided for measuring the inlet and outlet temperatures along with flow rate at the ambient conditions.
The general conditions for conducting the test are also defined within the standard ASHRAE 93-2003. The testing facility must be operating under steady state condition for determination of Qu data. Apart from that, values of Ti, Ta and GT are also required for calculations. The data pertaining to test is based on outdoor testing in summer of 1993. Also, it is recommended to conduct testing during the midday with clear sky having high beam radiation and mostly importantly, the radiation beams are normal to the surface of the collector. Hence, the condition for transmittance and absorption is quite commonly approximated to normal-incidence condition and is quite commonly written as(τα)n (Kalogirou, 2004, pp. 235-239).
For the first part, Flat Plate Solar Water Heater (FPSWH) is being used for the calculations. A pictorial representation of Flat Plate Collector (FPC) can be found in figure 1 showing its various components that are quite commonly utilized.

Figure SEQ Figure * ARABIC 1: Flat Plate Collector Pictorial View (Kalogirou, 2004, p. 241).When the solar radiation is passed through the transparent covering thereby impinging on the absorber surface, a major portion of the incident radiation is absorbed and subsequently, transported to the transfer medium of the fluid in tubes and/or it can also be utilized in a storage vessel for utilizing heat afterward. The side of casting and absorber plate’s underside is insulated in order to reduce the conduction losses. Apart from that, the liquid tubes can also be welded to the absorber plate thereby allowing them to be used as an integral part of the collector system. Also, the liquid tubes are connected with the headers from both sides. The transparent covering can be used for reducing the convectional losses through the glass and the absorber plate. The transparent covering can also help in reduction of radiation heat losses because the glass is quite transparent for short-wave radiations. However, it is quite opaque to long-wave radiation.
The testing was conducted in summers of 1993 having the following characteristics as shown in the table:
Outdoor testing on summer 1993
Average mass flow rate (kg/sec) (m) 0.00925
Insolation intensity (W/m2) Variable
Cp (J/kg K) 4178.4
Collector Area AC (m2) 0.155
Based on the provided data, the instantaneous efficiencies can be calculated by the following equation:
η= mCpTi-TaACGT (Struckmann,2008, pp. 1-3)
Table SEQ Table * ARABIC 1: Instantaneous Efficiency Calculation of FPSWHTime Steps Insolation (W/m2) Collector Inlet Temperature (°C) Collector Outlet Temperature (°C) Ambient temperature (°C) (Ta) Mass flow rate (kg/sec) Ti-TaGT(m2oC/W) Instantaneous Efficiencies
1 840 27.6 30.6 27.6 0.00925 0.00 89
2 840 27.0 30.0 26.7 0.00925 0.00 89
3 894 24.9 28.1 23.6 0.00925 0.00 89
4 896 24.6 27.8 22.6 0.00925 0.00 89
6 863 44.2 46.9 28.6 0.00925 0.02 78
7 861 41.2 43.8 24.4 0.00925 0.02 75
8 905 58.8 61.2 30.4 0.00925 0.03 66
9 902 61.2 63.4 30.4 0.00925 0.03 61
10 872 62.9 64.4 24.8 0.00925 0.04 43
11 871 85.4 86.4 30.4 0.00925 0.06 29
12 861 102.2 102.2 28.2 0.00925 0.09 0
The following plot is obtained that shows that instantaneous efficiency decreases to zero as the collector inlet temperature approaches collector outlet temperature:

Chart SEQ Chart * ARABIC 1: FPSWH Instantaneous EfficiencySimilarly, the second case of Evacuated Tube Solar Water Heater having outdoor data collected in summers of 2006:
Outdoor testing on summer 2006
Mass flow rate (kg/sec) Variable
Insolation intensity (W/m2) Variable
Cp (J/kg K) 4178.4
Collector Area (m2) 2
Conventional flat plate solar collectors were designed for warm and sunny environments; however, they are not that effective against the cloudy, cold and windy environments (Kalogirou, 2004, p. 241-244). Evacuated Tube Collectors (ETC) are quite commonly used for a different range of application as it comprises of a heat pipe inside of sealed tube as shown in figure 2:

Figure SEQ Figure * ARABIC 2: Evacuated Tube Collector (Kalogiru, 2004, p. 246).Based on the provided data, the instantaneous efficiencies can be calculated as shown in the table below:
Table SEQ Table * ARABIC 2: Instantaneous Efficiency Calculation of ETSWHTime Steps Insolation (W/m2) Collector Inlet Temperature (°C) Collector Outlet Temperature (°C) Ambient temperature (°C) Mass flow rate (kg/sec) Ti-Ta /GT
(m2C/W) Instantaneous Efficiencies
1 694 29.9 45.3 23.4 0.015 0.01 69
2 708 32.7 47.0 19.7 0.015 0.02 64
3 294 26.6 35.1 17.3 0.010 0.03 62
4 323 36.9 44.2 19.3 0.011 0.05 52
6 518 26.9 42.5 19.4 0.014 0.01 89
7 969 33.3 52.0 23.7 0.017 0.01 70
8 1052 38.4 63.8 18.5 0.012 0.02 61
9 524 19.7 33.9 18.4 0.012 0.00 70
10 327 30.6 39.6 18.4 0.011 0.04 60
11 946 42.7 58.2 22.0 0.019 0.02 67
12 1008 54.0 68.7 24.9 0.021 0.03 64
13 949 52.0 66.8 22.1 0.021 0.03 67
14 224 44.4 49.1 20.5 0.009 0.11 41
15 648 35.1 47.9 20.9 0.015 0.02 62
16 717 44.9 58.3 26.2 0.017 0.03 65
17 414 40.1 48.4 17.2 0.013 0.06 53
18 499 33.6 43.7 16.3 0.013 0.03 54
19 308 32.7 41.6 19.2 0.011 0.04 63
20 1032 45.6 61.1 20.5 0.020 0.02 63
21 177 30.5 35.4 15.14 0.010 0.09 58
22 462 50.6 61.4 18.57 0.017 0.07 81
23 589 50.7 60.9 18.47 0.020 0.05 72
24 1113 50.3 66.1 21.34 0.027 0.03 80
25 849 55.8 68.5 17.92 0.023 0.04 72
The following plot is obtained that shows that instantaneous efficiency decreases to zero as the collector inlet temperature approaches collector outlet temperature:

Chart SEQ Chart * ARABIC 2: ETSWH Instantaneous EfficiencyFor Concentrating Evacuated Tube Solar Water Heater (CETSWH), following data was collected through indoor testing in 2009:
Indoor testing on 2009
Average mass flow rate (kg/sec) 0.0087
Average illumination intensity (W/m2) 805
Cp (J/kg K) 4178.4
Collector Area (m2) 0.5
In Concentrating Evacuated Tube Solar Water Heater (CETSWH), a massive area of lenses and mirrors are used for focusing the sunlight beam onto the absorber surface (Kalogirou, 2004, p. 241-244). Based on above data, following instantaneous efficiencies can be calculated:
Table SEQ Table * ARABIC 3: Instantaneous Efficiency Calculation of CETSWHTime Steps Insolation (W/m2) Collector Inlet Temperature (°C) Collector Outlet Temperature (°C) Ambient temperature (°C) Mass flow rate (kg/sec) Ti-Ta /GT (m2C/W) Instantaneous Efficiencies
1 805 22.0 29.1 20.1 0.0087 0.002 64
2 805 27.4 35.0 20.1 0.0087 0.009 69
3 805 28.4 34.9 20.5 0.0087 0.010 59
4 805 32.5 39.3 20.4 0.0087 0.015 62
6 805 35.6 43.1 20.8 0.0087 0.018 68
7 805 36.3 43.7 21.0 0.0087 0.019 67
8 805 38.6 45.9 21.0 0.0087 0.022 65
9 805 39.0 46.0 21.3 0.0087 0.022 64
10 805 41.1 48.6 21.5 0.0087 0.024 68
11 805 42.6 50.2 21.6 0.0087 0.026 69
12 805 42.9 49.5 21.8 0.0087 0.026 60
13 805 45.1 52.8 21.9 0.0087 0.029 69
14 805 47.3 54.5 22.0 0.0087 0.031 64
15 805 47.6 54.4 22.0 0.0087 0.032 61
16 805 49.8 55.3 22.0 0.0087 0.035 50
17 805 52.1 58.4 22.2 0.0087 0.037 57
18 805 57.6 64.6 22.1 0.0087 0.044 64
19 805 58.3 64.7 22.3 0.0087 0.045 58
20 805 66.5 73.1 22.5 0.0087 0.055 60
21 805 66.6 74.5 22.5 0.0087 0.055 72
22 805 67.1 73.9 22.6 0.0087 0.055 61
23 805 78.2 85.3 22.5 0.0087 0.069 64
24 805 92.1 98.3 22.4 0.0087 0.087 56
25 805 108.3 113.6 22.5 0.0087 0.107 48

Chart SEQ Chart * ARABIC 3: CETSWH Instantaneous EfficiencyFollowing is the graphical representation of all the three plots:

Chart SEQ Chart * ARABIC 4: FPSWH, ETSWH and CETSWH Instantaneous Efficiency Comparison Scatter PlotA-2) Linear Regression AnalysisThe values of Fr(Tα) and Fr(UL) can be calculated by the point-slope formula for straight line equation:
y= mx+b (Webmath, 2016)
Here, linear regression analysis is conducted and the straight line obtained through linear regression would indicate the slope (m) and y-intercept (b) of each individual dataset. Here, the slope would indicate the value of Fr(Tα) and y-intercept would indicate the value of Fr(UL).
Before proceeding with the comparison based on Fr(Tα) and Fr(UL) values, it is important to know about the potential significance of the collector heat removal factor, collector’s overall heat loss coefficient and absorption coefficient. The product of Fr(Tα) indicates the component of solar energy penetrating into the collector’s transparent cover and the component of energy that is being absorbed. Secondly, the product of Fr(UL) indicates that collector will also transfer the amount of absorbed heat to the surroundings and hence the heat energy is lost to the environment. Hence, the below-mentioned comparison shows that the least amount of energy losses is observed through CETSWH system (Struckmann, 2008, pp. 1-4). It can also be visualized from above chart that most of the efficiencies are lying between 72-56% thereby indicating the effectiveness of CETSWH over FPSWH and ETSWH (University of Wisconsin–Madison, 2016, p. 3).

Chart SEQ Chart * ARABIC 5: Linear Regression Comparison of FPSWH, ETSWH and CETSWHTable SEQ Table * ARABIC 4: FPSWH, ETSWH and CETSWH Slope and Intercept ValuesFPSWH ETSWH CETSWH
Fr(Tα) 1033 Fr(Tα) 187.79 Fr(Tα) 121.46
FR UL 92.57 FR UL 71.83 FR UL 66.89
B) Suitability for Installation of Solar Water HeaterThe selected area is flat located at Portside Street, Nottingham in the United Kingdom (UK). The house comprises of a five room standard apartment having 5 family members, 2 showers and 3 wash basins. The locality in the UK is selected because hot water requirement is quite scared in hot climatic location, which was Jeddah, KSA in Assignment 1. The figure below shows the location of the apartment from Google Maps.

Figure SEQ Figure * ARABIC 3: Geographical Location of Portside, Nottingham (Google Maps Source).B-1) Suitability of the RoofAs depicted in below-mentioned aerial view of the apartment, it is evident that the building has a wide area of direct exposure to the sunlight at the location. Apart from that, the roof is flat without having any external roof area that could impede the sunlight exposure.

Figure SEQ Figure * ARABIC 4: Aerial View of the Apartment (Google Maps Source).B-2) Weather and Climatic ConditionsFrom figure 5, the average temperature and precipitation conditions are depicted showing that the mean maximum and minimum temperature throughout the calendar year varied from 21 oC and 2oC. The line of mean maximum daily temperature indicates the maximum temperature pertaining to an average day for each month within Nottingham, UK. Similarly, the minimum mean daily temperature indicates the mean minimum temperature that can be observed in Nottingham.

Figure SEQ Figure * ARABIC 5: Average Maximum and Minimum Temperatures in Nottingham, UK (Meteoblue, 2016).Nevertheless, another important factor in this regard is related to precipitation and cloud cover. Both these two factors seriously hinder the efficiency of solar water heating systems. Figure 6 shows the number of partly cloudy, cloudy, overcast, and sunny and precipitation days throughout the year. It can be visualized that the days having around 20% of the cloud cover are quite commonly considered as the sunny days. However, for the range of 20% to 80% of the cloud cover, they are considered to be the partly cloudy weather. For cloud cover greater than 80%, it is quite commonly considered as overcast.

Figure SEQ Figure * ARABIC 6: Cloud Condition and Precipitation in Nottingham, UK (Meteoblue, 2016).The maximum temperature profile analysis is also critical for determination of effectiveness and suitability of installation of solar water heater. The frost days profile clearly depicts the potential application of solar water heater during winter and autumn weathers. However, most of the days experience a maximum temperature of 5oC, 10oC and 15oC throughout the year that makes the usage of solar water heater during the mentioned time span.

Figure SEQ Figure * ARABIC 7: Maximum Temperature Profiles in Nottingham, UK (Meteoblue, 2016).The amount of precipitation as depicted in figure 7 shows that Nottingham faces an average of 14 dry days. Dry days lead towards less relative humidity in air thereby enhancing the capacity of air to hold water vapors. It could lead to reduced diffusive heat transfer from air to the solar water heater collector. Nevertheless, radiative heat transfer will be highly dependent on the cloud conditions.

Figure SEQ Figure * ARABIC 8: Amount of Precipitation in Nottingham, UK (Meteoblue, 2016, n.d.).Figure 5 clearly depicts the wide applicability of solar water heater in most of the months in a year. However, the overcast and cloudy weather can create severe impedance in solar water heating capacity and efficiency. Moreover, it can also negatively impact the heat absorption and thereby heating of water during January, November and December. Nonetheless, the months of June, July, August and September can prove to be some of the most efficient months in Nottingham for solar water heating purposes.
C) Estimation of Hot Water ConsumptionFor estimation of hot water consumption, the details of the water basin and showers are gathered for calculations. The calculations are performed through basic mathematics deduction formulae. However, the consumption per day per person data is assessed from the utility bill and rounded off for the sake of simplicity in calculations. It can be noted in part c-2 that only the data of November was analyzed because of lack of availability of data. The flowrate of warm water can be collected by either installation of a flow-meter or by fixing the warm water valve to a certain designated location. For the later one, a sample of warm water can be collected and the time noted. By dividing the collected volume to the time taken to collect the water will give the value of volumetric flowrate of warm water. However, for the sake of simplicity, the warm water valve will be fixed in the said position and the time for showers and wash basin usage will be recorded (Inspectapedia.com, 2016, n.d.). It should also be noted that Warm water consumption per Month for showers and wash basins together nearly make up the monthly consumption of November. The consumption values for hot water lies in the domain of low water consumption users as indicated by Cernunno (2016, n.d.)
C) Hot Water Consumption
   
  City Nottingham  
  Country UK  
  Type of House Flat (5 Room Standard Apartment)  
  Home Features  
  No of Family Members 5  
  Water Basins 3  
  Showers 2  
  Baths Nil  
   
C-1) Family Consumption of Hot Water Per Year   
  Months Consumption Per day per person Consumption per month  
  January 20 3100  
  February 22 3410  
  March 25 3875  
  April 30 4650  
  May 32 4960  
  June 27 4185  
  July 23 3565  
  August 24 3720  
  September 19 2945  
  October 21 3255  
  November 22 3410  
    Total 265 41075    
C) Hot Water Consumption
   
C-2) Shower, Bath and Basin Hot Water Consumption   
Showers Used (November)   Water Basins Used (November)
Consumption Consumption
Week 1 60   Week 1 16  
Week 2 62   Week 2 18  
Week 3 65   Week 3 15  
Week 4 68   Week 4 19  
Average Shower used per week 63.75 5 person-showers/week Average basin used/week 17 5 person-showers/week
Per Month 255 shower/month Per Month 68 shower/month
Per Year 3060 showers/yr Per Year 816 showers/yr
Average water usage in my household 10.2 liter/person/shower Average water usage in my household 12 liter/person/basin
Warm water consumption per week 650.25 liter/week Warm water consumption per week 204 liter/week
Warm water consumption per Month 2601 liter/month   Warm water consumption per Month 816 liter/month
D) Energy Content Calculation of Conventional Water HeaterFor calculation of energy content of the conventionally heated water, the inlet and outlet temperature is recorded around 6:00 PM. For the sake of simplicity, the system is considered to be a closed system for analyzing the energy content in the system. For calculation of it, sensible heat transfer is considered with any losses through convection:
Q= mCp∆T (Struckmann,2008, pp. 1-3)
D) Energy Content of Conventionally Heated Water
 
 
City Nottingham
 
Country UK
 
Type of House Flat (5 Room Standard Apartment)
Water Stream Features
 
Inlet Water Temperature 5 deg C  
Outlet Water Temperature 64 deg C  
Specific Heat Capacity 4.18 kJ/kg K   Consider steady state system having dm/dt =0 and no flow rates in and out of the heating vessel.
Volume of Water = 132 liter
Inlet Temperature = 5 deg C
Outlet Temperature = 64 deg C

We know that,   Q = mCp∆T   Volume of Gas Geyser in gal = 35 gal Volume of Gas Geyser in liter = 132 liter Volume of Gas Geyser in m3 = 0.13249 m3 Density of Water = 1000 kg/m3 Mass of Water in geyser = 7548 kg   Energy Content of Geyser = 1861433 kJ            
E) Heat Extracted from Solar Water Heater and Financial OutlooksExtracted heat can be calculated using the following equation:
mCpTi-Ta = ηxACGT (Struckmann,2008, pp. 1-3).
The data for analysis is taken from part (a) of Fixed Plate Solar Water Heater (FPSWH); however, the units for Cp have been changed to meet the calculation requirements:
Outdoor testing on summer 1993
Average mass flow rate (kg/sec) 0.00925
Insolation intensity (W/m2) Variable
Cp (Wh/kg K) 1.16
Collector Area (m2) 4
Table SEQ Table * ARABIC 5: Heat Extraction Calculation from FPSWHTime Steps Insolation (W/m2) Collector Inlet Temperature (°C) Collector Outlet Temperature (°C) Ambient temperature (°C) (Ta) Mass flow rate (kg/sec) Ti-Ta /GT (m2C/W) Instantaneous Efficiencies Heat Extracted(kWh)
1 840 27.6 30.6 27.6 0.00925 0.00 3 3.219
2 840 27.0 30.0 26.7 0.00925 0.00 3 0.003219
3 894 24.9 28.1 23.6 0.00925 0.00 3 0.0034336
4 896 24.6 27.8 22.6 0.00925 0.00 3 0.0034336
6 863 44.2 46.9 28.6 0.00925 0.02 3 0.0028971
7 861 41.2 43.8 24.4 0.00925 0.02 3 0.0027898
8 905 58.8 61.2 30.4 0.00925 0.03 3 0.0025752
9 902 61.2 63.4 30.4 0.00925 0.03 2 0.0023606
10 872 62.9 64.4 24.8 0.00925 0.04 2 0.0016095
11 871 85.4 86.4 30.4 0.00925 0.06 1 0.001073
12 861 102.2 102.2 28.2 0.00925 0.09 0 0
For assessing the financial contribution, UK Power (2016) has estimated electricity power consumption to be around 2000 kWh with the monthly rate of £61 per month. Based on that, the cost per kWh will be 61/2000 = 0.0305 £/month/kWh. Based on the data mentioned above, the total heat extracted is found about 3.2423914 kWh. Hence, the electricity saving of 0.0305×3.2423914 = 0.0989 £/month. However, for 12 months, it will be 0.0989×12 = 1.1872 £.
The Assignment 1 has Jeddah, KSA as the geographical location. However, Assignment 2 has Nottingham, the UK as the geographical location. Due to the significant changes in climate and weather, it is not appropriate to compare the previous data with the current one.
ConclusionAll in all, solar energy possesses tremendous potential for enhancement in the domain of renewable energy. More specifically, solar water heating can provide a cost effective alternative towards better household water heating solution in the cold climate to avoid extra cost incurred through conventional means of electricity and gas. However, selection of solar water heater is equally important and can enhance the
The usage of solar water heating systems can be quite effective in cold climate areas and can also prove to be somewhat economical. Apart from that, the instantaneous efficiencies are highly dependent on the collector types. The Concentrating Evacuated Tube Solar Water Heater (CETSWH) has been found to be the most efficient as compared to Fixed Plate Solar Water Heater (FPSWH) and Evacuated Tube Solar Water Heater (ETSWH) (Huang et al., 2001, p. 445). Solar water heater efficiency is also highly dependent on the geographical and climatic conditions of the vicinity. Direct exposure to sunlight would enhance the efficiency of solar water heater. Moreover, external environmental factors that include precipitation, maximum annual and minimum annual temperature also provide an enhanced outlook pertaining to changes in instantaneous efficiencies. However, ASHRAE 93-2003 has provided a comprehensive set of standard calculation that can enable calculation of instantaneous efficiencies together with Fr(Tα) and Fr(UL) values. The calculated values provide a clear depiction of the potential of choosing the best solar water heater system.

References
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Huang, B.J., Lin, T.H., Hung, W.C. and Sun, F.S., 2001. Performance evaluation of solar photovoltaic/thermal systems. Solar energy, 70(5), pp.443-448
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