# Various Comparison of Additional Conditions of Different Designed Thermal Solar Technology Systems with the Same Collector Field

Kenan Karacavuş

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Kenan Karacavuş. Various Comparison of Additional Conditions of Different Designed Thermal Solar Technology Systems with the Same Collector Field. Mechanics, Materials Science & Engineering Journal, 2017, 7, 10.2412/mmse.13.44.508. hal-01508706

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# Various Comparison of Additional Conditions of Different Designed Thermal Solar Technology Systems with the Same Collector Field

Kenan Karacavuş ¹.a

1. Asist. Prof., Edirne Technical College, University of Trakya, Edirne, Turkey

a. kenank@trakya.edu.tr

<figure><img src="image_2.png" /></figure>

DOI 10.2412/mmse.13.44.508

**Keywords:** solar energy, water heating, natural circulation system, pumped circulation system, flat plate solar collector, efficiency value, moving and follow-up system, photo-controlled unit.

**ABSTRACT.** It is important to research, develop and disseminate new and renewable energy sources instead of fossil fuels such as fossil fuels because of the energy demands of today.

The need for new and renewable energy sources and the efforts to efficiently use these resources have also been accelerated.

In this study which was made for the same purpose, in the study with the solar energy, in the Edirne related climate conditions for water heating, one is a closed system with fixed angle and natural circulation, the other is the closed system consisting of closed system with photo-controlled unit. Two experimental setups were designed. In these experimental setups, instantaneous, daily and average efficiency values for both systems were determined by using two standard flat-plate collectors of the same type, copper pipe, copper wing, flat plate and single glazed with equal collector area, during September, moving and follow-up system (following the sun with Photo-controlled Unit).

**Introduction.** In many applications made from solar energy, the conditions of operation and operation of the systems to be designed and applied are gaining importance in response to the question of how long and in which way the solar rays can be used, in consideration of the climate conditions to be applied. In order to be able to decide on applicable systems or systems that may be suitable for Edirne province climatic conditions, a "Closed System with Fixed Angle and Natural Circulation" which is a very common system applied in Edirne. Other that seem to have a high initial investment cost and thus are not very common to implement "Closed System with Moving and Follow-up system with Photo-Controlled Unit and Pumped Circulation System", these systems, which are called in September 2015 climate conditions,

1. System (First System): closed system with fixed angle natural circulation;

2. System (Second System): closed system with moving and follow-up system (following the sun with Photo-controlled Unit) and pumped circulation system.

**Materials**

If the two different systems in the experimental setup used in this study and the technical specifications of the elements forming these systems are explained in detail:

1) Closed system with fixed angle natural circulation: this system, which is called as (First System) 1st. System in the experimental setup;

* 2 pieces of 1930x930x85 mm size, 8 copper pipes, copper winged semiclective surface, monobloc polyurethane insulated flat-plate collector;

* 170 lt volume, polyurethane insulated, enamelled, pressurized hot water storage (boiler);
* Installation, and installation elements each insulated as a polyurethane sheath° a profile skeleton providing a fixed angle (approx. 40°).

The operating principle of this system is shown in Figure .1;

<figure><img src="image_3.png" /><figcaption>Fig. 1. Operating Principle of Closed system with fixed angle natural circulation.</figcaption></figure>

2) Closed system with moving and follow-up system (with Photo- controlled Unit) and pumped circulation system: This system, which is named as (second system) 2nd system in experimental setup;

* Flat-plate collectors of 2 pieces 1930x930x85 mm in size, with 8 copper tubes, copper wings, with a semiclective surface, monobloc polyurethane insulation;

* 1piece differential thermometer for circulation control in the system;

* 220 volts, 1 stage circulation pump with 3 speed control;

* A profile stand that allows the collectors to keep the sunlight at 90 ° with 4 photocell photo control units, which can be rotated 180 ° horizontally and vertically, with collectors carrying, 2 pieces 24V 12 " dish antenna motors;

* 170 lt volume, polyurethane insulated, enamelled, pressurized hot water storage (boiler);

* Flexible pipes and other installations, each of which is insulated with polyurethane casings.

This system operation principle diagram is shown in Figure 2.
<figure><img src="image_4.png" /><figcaption>Fig. 2. Operating Principle of closed system with moving and follow-up system (with Photo - controlled Unit) and pumped circulation system.</figcaption></figure>

In addition, there are 1piece self-programmed and datalogger-connected wind speed meter in the experimental setup, 1 piece solar thermometer (pyrometer) that can be connected to the datalogger, 1 piece digital thermometer connected to the datalogger that measures the ambient temperatures where the experiments are made, 7 pieces digital thermometers, which can be connected to the datalogger, were used to measure the temperature of the hot water tank (boiler), the main water temperature and the usage water temperature.

All measuring instruments are digital except for 1piece analogue flowmeter which is used to adjust the flow rate of the test system and they are connected to 2 pieces dataloggers for each system. However, in order to provide the time-controlled operation of the systems and measuring instruments, one timer was used in the electrical panel of the test apparatus.

Method

In the experimental setup, the collector temperatures of the two systems (t<sub>kg</sub>), Collector outlet temperatures (t<sub>kç</sub>), hot water storage (boiler) temperature (t<sub>b</sub>), mains water temperature (t<sub>se</sub>), utility water temperature (t<sub>ks</sub>), ambient temperature at which the experimental setup is located (t<sub>o</sub>), wind speed (V<sub>ort</sub>) After calibrating all the devices connected to 2 pieces datalogger in order to be able to determine values (E<sub>s</sub>) from the devices for which the values of the solar radiation per meter (m<sup>2</sup>) can be determined in advance, dataloggers all the systems in the test setup, Starting from 09:00 am, which is the starting time of every day, to 1:00 hour intervals starting at 17:00.

Starting from September 2015, experiments started. These 6 periodical values, which are formed every 1 hour intervals, were taken from a datalogger on a laptop computer after 17:00 hours and prepared in EXCEL and recorded for each day and every system in the experimental test protocol.
[1].
As the experiments continue during September 2015, these values are obtained by repeating for each day and processed for the test minutes. For these two systems, instantaneous efficiency values are firstly found in formula 1 [4].

$$ \eta_a = \frac{Q_f}{Q_{sol}} \qquad (1) $$

where $Q_f$ – the amount of useful heat to be provided by the system (kcal / day);

$Q_{sol}$ – amount of heat to be supplied by the system (kcal / day).

The amount of heat provided by the system [4];

$$ Q_f = m.c_p.(t_{ks} - t_{se}) \qquad (2) $$

where $m$ – daily water need to be heated in the system (kg / day);

$c_p$ – specific heat of the water to be heated (kcal / kg ° C);

$t_{ks}$ – desired water temperature (°C);

$t_{se}$ – mains water temperature (°C).

In addition, the amount of heat that must be supplied by the system in formula 1 [4].

It is found from formula 3 [4], that:

$$ Q_{sol} = E_s \cdot F_k \qquad (3) $$

where $E_s$ – intensity of radiation to the unit area (kcal / m2.day);

$F_k$ – total net collector area in the system (m2).

When all these values are determined and substituted in Formula.1, instantaneous efficiency values are found for each period in both systems. The average daily efficiency values of these instantaneous efficiency values are:

$$ \eta_o = \frac{\eta_{a1} + \eta_{a2} + ... + \eta_{as}}{s_p} \qquad (4) $$

where $\eta_{as}$ – instantaneous efficiency value for each period (%);

$s_p$ – number of period of measurement (number).

However, because of the days and the periods in which the negative experiences such as the low radiation intensity and the natural circulation are not observed from the experiments made during
September, only the measurement values of 6 days between 3 September - 2015 and 10 September - 2015 when the regular results were taken into account were taken into consideration. Average yield values of both systems for 6 days were found from formula 5 [4-5];

$$ \eta_{ort} = \frac{\eta_{go1} + \eta_{go2} + \dots + \eta_{gos}}{s_g} \qquad (5) $$

<table><caption>Table 1. Experiments results.</caption><thead><tr><th>Time</th><th>Experiment</th><th>Daily efficiency</th><th>Average value η<sub>go</sub></th></tr></thead><tbody><tr><td>Days</td><td>Dates</td><td>For 1st. System</td><td>For 2nd. System</td></tr><tr><td>1st. Day</td><td>03 / 09 / 2015</td><td>51,09</td><td>71,25</td></tr><tr><td>2nd. Day</td><td>04 / 09 / 2015</td><td>49,14</td><td>70,21</td></tr><tr><td>3rd. Day</td><td>06 / 09 / 2015</td><td>48,25</td><td>68,96</td></tr><tr><td>4th. Day</td><td>08 / 09 / 2015</td><td>52,61</td><td>72,02</td></tr><tr><td>5th. Day</td><td>09 / 09 / 2015</td><td>53,42</td><td>74,02</td></tr><tr><td>6th. Day</td><td>10 / 09 / 2015</td><td>51,18</td><td>72,28</td></tr><tr><td></td><td>Average efficiency η<sub>ort</sub></td><td>50,94</td><td>71,54</td></tr></tbody></table>

**Summary.** For both systems, the instantaneous efficiency values ($\eta_a$) of the 6 periods during the day are evaluated together with the operating parameters, and the daily average efficiency ($\eta_{go}$) values and average efficiency values ($\eta_{ort}$) of the 6 days in formula 4 [2] are calculated according to table 1. In addition, the curves of the efficiency values of the first system are shown in graph 1, the curves of the second system efficiency values are shown in graph 2 and the average efficiency values of both systems are shown in graph 3.

<figure><img src="image_5.png" /></figure>
<figure><img src="image_6.png" /><figcaption>Graph 2. Systematic Efficiency Curves for 2nd system.</figcaption></figure>

<figure><img src="image_7.png" /><figcaption>Graph 3. Mean Efficiency of Both Systems.</figcaption></figure>

From the values in table 1, it can be seen from the curves in graph 1, graph 2 and graph 3 that the closed system with moving and follow-up system (following the sun with Photo-controlled Unit) and
pumped circulation system, named as 2nd system, It is more efficient than a closed system with
naturel circulation.

We can say if it is so, "The system efficiency is high in the system because photo-control follows the continuous solar rays with photocell control in the quality system of the quality, the collector keeps the sunray perpendicular to 90° angle, and the circulation can be continuously circulated during the period.

References

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[2] Sukhatmane Sp, “Solar Energy Principles of Thermal Collection and Storage”, Mc Gramer Hill 1984, New Delhi.

[3] Atagündüz G. “Principles of Solar Energy Application”, 1989, İzmir, Turkey

[4] Öztürk A., Kiliç A., “Solar Energy Applications”, Kipaş Yayncılık, 1983, İstanbul, Turkey

[5] Kreider J.F., Keith F., “Solar Energy Handbook”, Mc. Gaw Hill Book, 1981

[6] Nguyen The Bao (2016). *Numerical Modelling of Basin Type Solar Stills*. Mechanics, Materials Science & Engineering, Vol. 4. doi:10.13140/RG.2.1.4601.9449

[7] Howell Y., Becerny JA "Güneş Enerjisi ile Mühendis Kılavuzu", Güneş Energi Hizmetleri (1989)

[8] F. Rinaldi, M. Binotti, A. Giostri, G. Manzolini. Comparison of Linear and Point Focus Collectors in Solar Power Plants, Proceedings of the SolarPACES 2013 International Conference, Volume 49, 2014, Pages 1491-1500, doi:10.1016/j.egypro.2014.03.158