Thermodynamic Analysis of an Experimental Model of a Solar-Heat Supply System
and Daniyar Kerimkulov 2Round 1
Reviewer 1 Report
This paper studies thermodynamic analysis of a solar heat supply system in a cold region of Kazakhstan, experimentally. They compared the effect of single and double glazing heat-insulating windows as the solar collector. This quiet interesting topic. Unfortunately, they seem don't pay attention to its writing style in terms of grammar and its understanding. So many incomplete sentences found and the abstract was too long and hard to be understood. Moreover the introduction consist of two paragraphs with remarkable long.
We believe if the authors restructuring and proofreading the manuscript, it could be much more better and easy to understand. We have made some advice and critics to improve the quality in the file, attached.
Comments for author File: 
Comments.pdf
Author Response
The authors rearranged and proofread the manuscript
Reviewer 2 Report
The authors study a new design that includes various optimization strategies. In the course of the study, an experimental setup was developed and investigated, optimizing design parameters that can help in reducing the complexity of the classification system.
Also, in this article paper that obtained results, it was found that double glazing is more effective than single glazing. Moreover, it has also been investigated that the efficiency of collector F' depends on the thickness of the absorbing plate.
Furthermore, results of experiments on the seasonal efficiency of the heating system in a two-circuit solar system with thermosiphon circulation in winter conditions with dense clouds and sunny weather are presented. I
Because of these points, I recommend accepting the article paper in its present form.
Author Response
Thank you for recommending to accept the article
Author Response File: 
Author Response.docx
Reviewer 3 Report
The author describes the “Thermodynamic analysis of an experimental model of a solar heat supply system”.
· Article title clearly gives the contribution and novelty of the article.
· Need to improve the quality of Fig. 3.
· The paper is well described and can be accepted for publication.
Comments for author File: Comments.docx
Author Response
I have removed Figure 3.
Thank you for the fact that the article has been accepted for publication.
Author Response File: Author Response.docx
Round 2
Reviewer 1 Report
the manuscript seems had been proofread so that it is much more better. However, some suggestions haven't been revised yet (the detail can be seen in the attached file). Whenever the authors revised all suggestion, I do believe this manuscript is worthy to be published in this journal.
Comments for author File: Comments.pdf
Author Response
Response to the reviewer
1.The introduction is easier to be understood, however it's still too long for a paragraph. We suggest the authors to split into some paragraphs with its own main idea and related to each other.
Answer. I have broken it into 2 paragraphs
- Introduction
In the works [1,2], the main attention is paid to various systems with low energy consumption and low refrigerant consumption, which can effectively provide comfortable indoor air conditioning parameters in India. Researchers have developed two mathematical models - energy consumption and refrigerant consumption, which reduce the need for refrigerant. We also studied the possibility of using 65% of the parameter for indoor use, for use as the main tool in buildings with low energy consumption and the area of indoor air conditioning and water heating compared to traditional systems. In [3], the development of a mathematical model of the material of enclosing structures in the energy consumption of the room is proposed. In the article [4], four heating systems using solar-powered heat pumps were designed, and photovoltaic systems of gas stations and photovoltaic cells connected to a water heat pump were modeled. Photovoltaic systems in combination with an air pump, have the possibility of connecting systems with a water heat pump. energy in the grid, which makes this technology the most environmentally friendly. The article [5] investigates two of the most popular methods of modernization - covering the buildings of cities with a predominance of cooling. In [6], a complex energy system under study for heating the main room with power from a heat pump was developed, when powered by electric current, the supply of hot water to the heat pump increases efficiency (efficiency), since the temperature with an air source. Each system is carefully designed to maintain thermal comfort conditions at a high level. In [7], a mathematical analysis of solar water heating was developed, which accounts for the majority of all applications on the market. An article [8] was developed that could potentially eliminate these problems. In [9], systems were developed and investigated in which water is used as a working fluid, and this water is used in the systems. The problems of the solar heat supply system are traditionally associated with the occurrence of corrosion. In the study [10], an approach to the mathematical analysis of efficiency is proposed for calculating the properties of a passing object, and the characteristics of its corresponding environment. In the document, after the description, an explanatory application of this method is presented, taking into account the emphasis on the installation. The results obtained are consistent with the results of the generally accepted standard thermo-dynamic analysis of the stationary state. with the same user needs, the average primary power is approximately equal to a standard gas burner. This result practically does not depend on (with glazing) the operation of the collector.
In the article [11], the equations of thermos hydraulic characteristics of various roughness’s of a conical protrusion were developed and the characteristic conditions were considered. The method of flow and temperature increase was used in the study. The roughness of the edges of the ledge was assessed. The article [12] describes the evaluation using working radiation. The results of experimental analysis in transient modes under conditions of zero solar radiation are shown and discussed, and a characteristic efficiency of 3.23 was obtained. The article [13] considers the feed from the point of view of the hydraulic layout and climatic conditions. For comparison with the electric water heating system, three common hot water systems were selected — a conventional solar hot water system, a solar combined system with one tank, and a solar combined system with two tanks, and their technical and economic aspects were evaluated. Additional capital costs for solar combined systems. The article [14] investigates the characteristics of the efficiency of a heat pump, which consisted in evaluating their operation, where the efficiency of the system ranged from 2.5 to 5.0. In the study [15], a solar heat pump system was proposed that could operate in serial or parallel mode. In the article [16] the water heater is investigated. System efficiency (COP) achieves greater icing heating provides excellent evaporator icing delay. In the article [17], the evaporator and condenser are based on the continuity and conservation equations. The pressure and density of the refrigerant are given in the corresponding tables. The results of comparing the simulation data with what is necessary during modeling to reduce the required time and some mechanical modifications for the presented prototype are also presented. In the article [18], the work is aimed at ensuring that a new mathematical model of SAP performance is currently being carried out, has been developed in good faith, the presence of differences can lead to serious inconsistencies when comparing the analysis of different configurations. In the article [19], a solar heat supply system was developed, in which it was determined that the COP level changes significantly with changes in solar radiation based on the mathematical theory of convection, which allows heat to be absorbed due to a higher ambient temperature and a lower evaporation temperature. In the study [20], a mathematical model of thermal characteristics was developed, an analysis was carried out for the refrigerant R134a using a solar collector with one lid. In the article [21], a capacious water tank was investigated under vacuum conditions. The equations of nonstationary state defining mass, momentum, concentration and conservation of energy are developed and investigated. Numerical data showed an increase in the gutter edge by at least 19.78%. In the article [22], a mathematical model was developed and simulation modeling of transfer phenomena was carried out. Numerical results have also been obtained that are absorbed faster than zeolite. In addition, a static study of the adsorption–ejection system is carried out to obtain an important solar efficiency.
When the intense solar radiation ambient temperature change, COP values for the system change depending on different structural schemes. This study is a new design that includes various optimization strategies. In the course of the study, an experimental setup was developed and investigated, optimizing design parameters that can help in reducing the complexity of the classification system.
- it is recommended to make a glossary for the parameter notations used in the manuscript. they haven't available completely yet. it is confusing reader to understand.
Answer. The notation is all correct, they are accessible and does not confuse the reader!! who is engaged in thermodynamics, and especially thermal processes in solar heat supply systems, it's all clear to him!! And no glossaries are needed!! All these are well-known laws
- Figure 3 should be defined clearly. it is too short.
Answer. Figure 3 shows the test bench where the experimental work was carried out. The test bench was made and investigated on the farm of the Republic of Kazakhstan. The stand consists of 4 flat solar collectors. and heat-insulating translucent glass with double glazing with reduced pressure. The coolant is made of thin-walled corrugated stainless pipe. The heat from the solar flow heats the liquid removed from the collector, and cold water from the siphon enters its place. There is a constant circulation of heat, which increases the efficiency of heat transfer by eliminating additional partitions between the panel and thermal insulation.
4.This sentence also too short. It should be expanded.
Answer. Industrial design and general view of a two-circuit solar installation. As can be seen from this figure As a whole, the translucent glazing of the solar installation is reduced, and there is also a cooling pipe. Water from the flat solar collector of the siphon takes its place, removing heat and eliminating the partitions of the thermal energy panel. Water from a flat solar collector enters a circulation pump — a household appliance for pumping liquid. An electric motor and a working shaft are installed in the housing. Then the rotor turns on, which begins to rotate the impeller, which creates a reduced pressure at the inlet and an increased pressure at the outlet. The circulating water enters the spiral-to-spiral heat exchanger in the intensity range, after which the water is pumped into the storage tank. There is also an expansion tank — an element of the heating system designed to receive excess water from its thermal expansion due to heating.
5.The unit should be W/m2
Answer. Yes you are right
- Тhe text is too hard to be read
Answer. Figure 7 a,b shows changes in collector efficiency: (a) tube pitch; (b) the thickness of the absorbing plate. The thickness under the absorbing plate ranged from 50% to 65%, and the thickness above the absorbing plate ranged from 63% to 77%
- COP systems with variable evaporator temperature.
Answer. The results showed that the COP increases with an increase in the temperature of the heat pump evaporator within the range considered in this paper. Thus, flat solar collectors are better suited for operation in winter.
