Comparison of Application Effects of Capillary Radiation Heat Pump and Electric Heating Wire in Greenhouse Seedling Cultivation

Round 1

Reviewer 1 Report

- The references are incorrectly cited

- In Section 1 the Authors need to clearly state what knowledge gap their work will fill COMPARED TO the current status on the investigated topic

- The accuracy of the experimental equipment is missing 

- The uncertainty propagation analysis is missing

- A detailed description of the heat pump is missing

- The assumptions in Section 4 need to be supported by suitable references

- In Section 5 the limitations and the necessary future developments need to be summarized 

Author Response

Response to Reviewer 1 Comments

Dear Reviewer,

Thank you for your useful comments and suggestions on our manuscript, which are valuable for improving the quality of our manuscript.

We have modified the manuscript accordingly, and detailed corrections are listed below point by point. In the revised manuscript, all changes marked in red. If you have any further questions or concerns, please feel free to contact us.

The manuscript has been resubmitted to “Agriculture”. We look forward to your positive response.

Sincerely yours,

 

Qiu Tu

 

 

 

 

 

 

 

 

 

Point1: The references are incorrectly cited.

Response 1:   

We changed the citation method of references.

Point 2：In Section 1 the Authors need to clearly state what knowledge gap their work will fill COMPARED TO the current status on the investigated topic.

Response 2:   

The application of current heat pump technologies in the greenhouse heating has promoted the development of industrialized vegetable planting, but there are still some problems. For example, the heat pump with water as the heat exchange medium has the risk of water leakage and freezing damage of the pipeline. The heat pump is used to heat the whole greenhouse, instead of directly adjusting the temperature of soil/substrate and vegetable rhizosphere, resulting in limited increase of temperature. If the whole space of the greenhouse is heated to a set target temperature, the heat load of the greenhouse is some times of heat needed for vegetable seedling growth. In fact, most of the heat in the upper part of the greenhouse can't be used for the seedling heating, which is wasted in vain. As a result, the equipment investment cost is several times higher than that required for local temperature control. At present, the heat pump technology is difficult to accurately control the temperature and humidity to meet the required conditions of vegetable seedlings at different stages, especially grafting seedlings. The application of heat pump in greenhouse seedling cultivation has not been reported yet. Therefore, a safe, efficient and precise temperature control system with strong adaptability is urgently needed in the greenhouse seedling cultivation in winter.

The MDCRHP was first applied in the vegetable seedling cultivation, and the local temperature and humidity control method was adopted to obtain precise temperature regulation for vegetable seedling and achieve energy-saving.

Point 3： The accuracy of the experimental equipment is missing 

Response 3:   

The accuracy of an instrument is usually expressed in terms of uncertainty, shown in Table 1.

Table 1 Uncertainties of the test parameters

Parameters	Instrument	Uncertainty	Full scale
Temperature in seedling beds (a-h,A-H)	T-type thermocouple	±0.5 ℃	-50-200 ℃
Relative humidity	Humidity transmitter	±0.5 %	0-100%
Electricity energy consumption	Electricity meter	±0.2 %	¾

 

Point 4：The uncertainty propagation analysis is missing

Response 4:   

Uncertainties of the test parameters are shown in Table 1

Point 5：A detailed description of the heat pump is missing

Response 5:   

The arrow indicates the refrigerant flow direction during heating operation. In detail, the variable-frequency compressor discharges high-temperature vapor refrigerant, enters the capillary group in each seedling bed through the four-way valve, radiates heat to the air in the seedling bed, and the air is heated. And then the refrigerant enters the main liquid pipe, flows into the evaporator after the throttle of the main electronic expansion valve (MEEV). The refrigerant absorbs air energy from outside air. Finally it returns to the compressor to complete the heating cycle. During this cycle, the electronic expansion valve (EEVi) and the solenoid valve (SV) of thermo-on indoor units are opened, but those of the thermo-off indoor units are closed, so as to achieve zero energy consumption. The compressor frequency is adjusted according to a certain target temperature of seedling or substrate. The MEEV opening is regulated according to a certain target super-heating degree, which is defined as the temperature different between suction temperature (T_s) and evaporator coil temperature (T_def).

Point 6：The assumptions in Section 4 need to be supported by suitable references.

Response 6:   

The electric heating wire was used for heating. The materials include electric heating wire and thermostat. The unit prices of the electric wire and the thermostat are ¥40 /100m and ¥85 respectively, which are presented by Ningbo electric heating equipment factory.

The material cost of 3 HP heat pump was given by Zhongguang Electric Appliance Co. Ltd.

 

Point 7： In Section 5 the limitations and the necessary future developments need to be summarized.

Response 6:   

At present, the two tidal seedbeds are fixed, so the capillary groups on the seedling beds and the connecting pipe between the capillary groups and outdoor unit are fixed. In practice, for greenhouse vegetable seedling cultivation, in order to improve the utilization rate per unit area of the greenhouse, the tidal seedling beds are designed to be movable, so the connecting pipe between the outdoor unit and the indoor units of the heat pump needs to be designed to be movable with the seedling beds. This problem will be solved in the next step.

 

 

 

Author Response File: Author Response.pdf

Reviewer 2 Report

1. An interesting idea and the goal is also interesting: to compare two options for heating greenhouses. The description of the experimental equipment shows that the research Agricultural Experimental Park has two adjacent independent small glass greenhouses at its disposal. Two tidal seedling beds are installed in each glasshouse. The aim was to compare two different methods of heating these greenhouses. Electric heating wire (EWH) and heating using a heat pump, in this work called multi-connected direct expansion capillary radiation heat pump (MDCRHP).

2. In order to assess whether the method MDCRHP = multi-connected direct expansion capillary radiation heat pump (MDCRHP) or EHW = electric heating wire (EWH) is more advantageous for heating, it would be necessary to measure in both systems at the same time with the same outdoor ambient weather parameters. The work does not even include basic meteorological data, i.e. temperature and intensity of solar radiation at the time of measurement.

3. However, the authors made measurements in different periods, MDCRHP as shown in Figure 6 on days (a) Target condensation temperature of 38 ℃ (February 6 to 7, 2022, cloudy days), Target condensation temperature of 42 ℃ (February 7 to 8, 2022, cloudy days), (c) Target condensation temperature of 46 ℃ (January 28 to 29, 2022, cloudy days). It is not stated at which outdoor temperatures, humidity and solar radiation were measured.

EHW = electric heating wire (EWH) was measured as shown in Figure 7 a) Electric heating wire with a spacing of 5cm (February 10 to 11, 2022, cloudy and rainy days), (b) Electric heating wire a spacing of 10 cm (February 11-12, 2022, cloudy days). It is not stated at which outdoor temperatures, humidity and solar radiation were measured.

4. The description of the measurement methodology is too extensive, but very confusing and chaotic. It is necessary to briefly describe the principles of both tested methods and their differences in construction. Focus on a brief description of two different heat sources with an indication of the basic parameters. Furthermore, explain the difference in the way heat is transmitted from the source to the heated space. In the case of MDCRHP, is it heat transmitted by radiation, or convection, conduction or a combination of different methods of heat sharing? Appropriate pictures should also be adapted to this description, which should better describe the construction of heating and the location of the measuring sensors.

5. In the description in section 2.1, the basic parameters of the heat pump must be stated.

6. There are a lot of abbreviations in the text, so it would be appropriate to provide a separate list of abbreviations. Use abbreviations in the text as little as possible, only in figures and tables.

7. The results are not evaluated by statistics, in terms of the significance of the differences between the investigated heating systems.

8. In figures 7, 8, etc., choose the lines so that the course can be clearly seen. The existing images are very confusing in terms of lines. To show in these pictures what follows from them - it is not clear from this.

9. There are a number of formal deficiencies and errors in the work. E.g. in tab. 1 are mysterious quantities and the units EP/kW.h should probably be kWh; it is inappropriate to write the value sign divided by the unit, e.g. Tcon / ℃, this must be corrected to the correct form of notation.

10. In the text there are many times the number and unit without a space - it needs to be corrected everywhere.

11. The cited works (references) are very insufficient, it is necessary to find other scientific works focused on this issue in Scopus and WOS.

12. Compare the results of your own research with the results of cited papers in the Discussion section.

Conclusion

Overall, I recommend a complete overhaul and try to be a more concise and clear form.

Author Response

Response to Reviewer 2 Comments

Dear Reviewer,

Thank you for your useful comments and suggestions on our manuscript, which are valuable for improving the quality of our manuscript.

We have modified the manuscript accordingly, and detailed corrections are listed below point by point. In the revised manuscript, all changes marked in red. If you have any further questions or concerns, please feel free to contact us.

The manuscript has been resubmitted to “Agriculture”. We look forward to your positive response.

Sincerely yours,

Qiu Tu

 

 

 

 

 

 

 

 

 

1. An interesting idea and the goal is also interesting: to compare two options for heating greenhouses. The description of the experimental equipment shows that the research Agricultural Experimental Park has two adjacent independent small glass greenhouses at its disposal. Two tidal seedling beds are installed in each glasshouse. The aim was to compare two different methods of heating these greenhouses. Electric heating wire (EWH) and heating using a heat pump, in this work called multi-connected direct expansion capillary radiation heat pump (MDCRHP).

Response 1: No problem

2. In order to assess whether the method MDCRHP = multi-connected direct expansion capillary radiation heat pump (MDCRHP) or EHW = electric heating wire (EWH) is more advantageous for heating, it would be necessary to measure in both systems at the same time with the same outdoor ambient weather parameters. The work does not even include basic meteorological data, i.e. temperature and intensity of solar radiation at the time of measurement.

Response 2:  

The MDCRHP was composed of two capillary groups (indoor uits) in two seedling beds. If the comparative tests of capillary radiation heating and electric heating line heating are conducted on two seedlin beds at the same time, the electricity energy consumption of each seedling bed is too low, which will lead to large systematic error. Therefore, the two heating methods are tested separately instead of synchronously. When comparing the performance of the two heating methods, the comparison was made under the conditions of close ambient temperature and basically equivalent heating effect (air/substrate temperature in the seedling bed), as shown in Table 2.

During the whole test process, the outdoor ambient temperature (T_ao) and greenhouse ambient temperature (T_ai) were simultaneously tested while the air or substrate temperatures in the seedbed were tested. Solar radiation was not tested, but a thermocouple was installed in the greenhouse to measure the greenhouse ambient temperature, which can reflect the solar radiation.

3. However, the authors made measurements in different periods, MDCRHP as shown in Figure 6 on days (a) Target condensation temperature of 38 ℃ (February 6 to 7, 2022, cloudy days), Target condensation temperature of 42 ℃ (February 7 to 8, 2022, cloudy days), (c) Target condensation temperature of 46 ℃ (January 28 to 29, 2022, cloudy days). It is not stated at which outdoor temperatures, humidity and solar radiation were measured.

EHW = electric heating wire (EWH) was measured as shown in Figure 7 a) Electric heating wire with a spacing of 5cm (February 10 to 11, 2022, cloudy and rainy days), (b) Electric heating wire a spacing of 10 cm (February 11-12, 2022, cloudy days). It is not stated at which outdoor temperatures, humidity and solar radiation were measured.

Response 3:   

During all the tests, the outdoor ambient temperature (T_ao) and relative humidity (RH), the temperature and relative humidity in the seedling beds, and the indoor ambient temperature (T_ai) and relative humidity in the greenhouse are tested synchronously. The outdoor ambient temperatures are shown in Figure 6,7,9,10,11. But relative humidities are not shown in these figures. Relative humidities were discussed in Section 3.4, shown in Figure 12.

Solar radiation was not measured. The indoor temperature can reflect influence of solar radiation on the air and substrate temperatures in seedling beds.

4. The description of the measurement methodology is too extensive, but very confusing and chaotic. It is necessary to briefly describe the principles of both tested methods and their differences in construction. Focus on a brief description of two different heat sources with an indication of the basic parameters. Furthermore, explain the difference in the way heat is transmitted from the source to the heated space. In the case of MDCRHP, is it heat transmitted by radiation, or convection, conduction or a combination of different methods of heat sharing? Appropriate pictures should also be adapted to this description, which should better describe the construction of heating and the location of the measuring sensors.

Response 4:  

The contents of the measurement methodology is briefly introduced as follows:

The purpose of the experiment was to comparatively test the effects of the MDCRHP and EHW heating on the air temperature, substrate temperature and relative humidity in the seedling bed, and to measure the electricity energy consumption when the closed and open local temperature control were used.

For the MDCRHP, under the condition of different condensation temperatures, variations of air temperature fields, relative humidities in seedling beds and electricity energy consumptions with time were tested. The condensation temperature is the saturation temperature corresponding to the discharge pressure of the heat pump unit. When the MDCRHP operated, the compressor operation frequency was controlled according to a certain condensation temperature. The condensation temperature was set by the monitoring software. For the EWH, under the condition of different electric heating wire spacings, variations of these parameters with time were tested.

After the air temperature distribution measurements of two heating methods in the seedling bed were completed, the seedling trays were placed on the seedling bed for seedling cultivation with tray substrate. The variations of the substrate temperature fields, relative humidities in seedling beds and electricity energy consumptions with time were tested.

During the test process, the average temperature detected by the temperature sensors was used to control the thermo-on/ thermo-off state of each seedling bed.

5. In the description in section 2.1, the basic parameters of the heat pump must be stated.

Response 5:  

The basic parameters of the heat pump include the operation basic parameters such as condensation temperature (T_con) and operation frequency, and performance parameters such as heating effect, coefficient of performance (COP) and electric power. The heating capacity and COP can not be measured in the greenhouse because it must be tested in enthalpy difference Lab. In this work, the air and substrate temperatures in the seedling beds can reflect the heating effect. The electricity energy consumption (kWh) can be easily measured by the electricity meter, and can be used to evaluate energy conservation of the heat pump.

6. There are a lot of abbreviations in the text, so it would be appropriate to provide a separate list of abbreviations. Use abbreviations in the text as little as possible, only in figures and tables.

Response 6:  

Nomenclature

Abbreviation
ASHP	Air source heat pump
CLTC	Closed local temperature control
COP	Coefficient of performance
EEVi	Electronic expansion valve of capillary group
EP	Electricity energy consumption  KWh
EWH	Electric heating wire
GSHP	Ground source heat pump
MEEV	Electronic expansion valve in liquid pipe of outdoor unit
MDCRHP	Multi-connected direct expansion capillary radiation heat pump
RH	relative humidity
SAASHP	Solar assisted air source heat pump
SAGSHP	solar assisted ground source heat pump
SAHP	Solar-assisted heat pump
SV	Solenoid valve
WSHP	Water source heat pump
Symbols
Pd	Discharge pressure  bar
Ps	Suction pressure  bar
Tai,compa	Indoor ambient temperature of adjacent comparable greenhouse  °C
Tao	Outdoor ambient temperature  °C
Tavg,air	Average air temperature in seedling bed  °C
Tavg,subs	Average substrate temperature in seedling bed  °C
Tcon	Condensation temperature  °C
Td	Discharge temperature  °C
Tdef	Evaporator coil temperature  °C
Ts	Suction temperature  °C
Subscript
1,2	1#, 2# seedling bed
0.1,0.5	At the hght of 0.1 and 0.5 m
ao	Outside air
e	Eastt side of each seedling bed
w	West  side of each seedling bed
ΔT	Temperature different

 

7. The results are not evaluated by statistics, in terms of the significance of the differences between the investigated heating systems.

Response 7:  

About controlling temperature, from the research situation, the increase range of the air temperature and substrate temperature in the greenhouse was generally about 2-7 ℃ and 2-10 ℃,respectively. There is less research on the air temperature field distribution in the greenhouse. In this work, the MDCRHP can increase air temperature of 11,12 and 14 ℃ in the seedling beds under the condition of the condensation temperature of 38, 42 and 46 ℃, respectively. The increase amplitude can be further lifted by improving the condensation temperature, i.e. the operation frequency of the compressor. Obviously, the heating effect of the closed local controlling temperature method is superior to that in the cited papers.

8. In figures 7, 9, etc., choose the lines so that the course can be clearly seen. The existing images are very confusing in terms of lines. To show in these pictures what follows from them - it is not clear from this.

Response 8:  

In this manuscript, in order to verify the uniformity of the air temperature fields in the seedling beds, the air temperatures in the seedling beds at different positions in the horizontal directions and at the heights of 0.1M and 0.5m were tested experimentally. The average air temperatures and substrate temperatures of the east and west sides of seedling beds at different heights was given in Figure 7 and 9, respectively. From the test results, the temperature fields were evenly distributed, and the difference was less than 1.0 ℃. So these temperature curves are very close. But these curves can be distinguished from the colors. If these curves are to be completely and clearly partitioned, only one or two temperatures in the seedling bed can be given in Figure 7 and 9, but the temperatures at different positions and heights cannot be given, and the uniformity of the temperature field cannot be proved.

9. There are a number of formal deficiencies and errors in the work. E.g. in tab. 1 are mysterious quantities and the units EP/kW.h should probably be kWh; it is inappropriate to write the value sign divided by the unit, e.g. Tcon / ℃, this must be corrected to the correct form of notation.

Response 9:  

The EP unit of “kW.h” was revised as “kWh”. And the “ /”  before the unit was changed to “( )”

10. In the text there are many times the number and unit without a space - it needs to be corrected everywhere.

Response 10:  

We added a space between the number and unit.

11. The cited works (references) are very insufficient, it is necessary to find other scientific works focused on this issue in Scopus and WOS.

Response 11:  

Some references were added in this manuscript. In this manuscript, there are 40 references.These added references are listed as follows.

2. Li, P.P.; Hu Y.G. Thermal Preservation Effect of Multi-film Covering and Heating Wire in Plastic Greenhouses in Winter. Transactions of the Chinese Society of Agricultural Engineering (Transactions of the CSAE), 2002,18(2),76-79.
3. 3. Luo,J; Xue,W.; Shao,H.B. Thermo-economic comparison of coal-fired boiler-based and groundwater-heat-pump based heating and cooling solution-A case study on a greenhouse in Hubei, China. Energy & Buildings 2020, 223,110214.
4. Benli, H.;Durmus A. Evaluation of ground-source heat pump combined latent heat storage system performance in greenhouse heating. Energy Build.2009,41, 220-228.
5. 2 Urchueguía J.F.; Zacarés,M.; Corberán,J.M.; Montero,A.; Martos, J.;Witte,H. Comparison between the energy performance of a ground coupled water to water heat pump system and an air to water heat pump system for heating and cooling in typical conditions of the European Mediterranean Coast, Energy Convers. Manag. 2008,49 (10),2917–2923.
6. 2 Barbaresi,A.; V. Maioli,V.; Bovo,M.; Tinti,F.; Torreggiani,D.; Tassinari,P. Application of basket geothermal heat exchangers for sustainable greenhouse cultivation. Renewable and Sustainable Energy Reviews. 2020,129,109928.
7. 2 Choi,J.M.; Park,Y.J.; Kang,S.H. Temperature distribution and performance of ground-coupled multi-heat pump systems for a greenhouse。Renewable Energy 2014, 65,49-55.
8. 3 Aye,L.; Fuller, R.J.; Canal,A. Evaluation of a heat pump system for greenhouse heating. International Journal of Thermal Sciences. 2010,49, 202–208.
9. 3 Mehrpooya,M.; Hemmatabady, H.; Ahmadi, M.H. Optimization of performance of Combined Solar Collector-Geothermal Heat Pump Systems to supply thermal load needed for heating greenhouses. Energy Convers Manage. 2015,97, 382–392.
10. 3 Giovanni Russo, Alexandros S. Anifantis, Giuseppe Verdiani,Giacomo Scarascia Mugnozza.Environmental analysis of geothermal heat pump and LPG greenhouse heating systems. Biosystems Engineering, 2014,127,11-23.

 

12. Compare the results of your own research with the results of cited papers in the Discussion section.

Response 12:  

The heating effect, i.e. air temperature and substrate temperature in seedling beds, energy saving rate, relative humidity in seedling beds, energy saving are compared with the results in the cited papers.

About controlling temperature, from the research situation, the increase range of the air temperature and substrate temperature in the greenhouse was generally about 2-7 ℃ and 2-10 ℃,respectively. There is less research on the air temperature field distribution in the greenhouse. In this work, the MDCRHP can increase air temperature of 11,12 and 14 ℃ in the seedling beds  under the condition of the condensation temperature of 38, 42 and 46 ℃, respectively. And the increase amplitude can be further increased by improving the condensation temperature, i.e. the operation frequency of the compressor. Obviously, the heating effect of the closed local controlling temperature method is superior to that in the cited papers.

Humidity regulation is very critical to seedling cultivation, but there is relatively little research at present. The previous test results show that the evaporation of water vapor in the greenhouse will reduce the relative humidity of the air during the operation of the heat pump system. However, for grafting seedling cultivation, the relative humidity during grafting healing period is required to be more than 95%. Obviously the current heat pump and open temperature controlling method is not suitable for grafting seedling cultivation.

In terms of energy saving, the test results show that the energy-saving rate of the MDCRHP was 47 %-50.7 % compared with the electric heating wire (EHW). The energy-saving rate is higher than that of previous work [1,21,22].

These supplementary contents have been added in the corresponding places in the manuscript.

Conclusion

Overall, I recommend a complete overhaul and try to be a more concise and clear form.

We have comprehensively and conscientiously revised and improved the full manuscript.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

·        In Section 1 the Authors need to clearly state what knowledge gap their work will fill COMPARED TO the current status on the investigated topic

·        The uncertainty propagation analysis is missing

·        The use of contracted forms needs to be avoided

·        What refrigerant was used?

Author Response

Response to Reviewer 1 Comments

Dear Reviewer,

Thank you for your useful comments and suggestions on our manuscript, again, which are valuable for improving the quality of our manuscript.

We have modified the manuscript accordingly, and detailed corrections are listed below point by point. In the revised manuscript, all changes marked in red. If you have any further questions or concerns, please feel free to contact us.

The manuscript has been resubmitted to “Agriculture”. We look forward to your positive response.

Sincerely yours,

 

Qiu Tu

 

 

 

 

 

 

 

 

 

Point1:  In Section 1 the Authors need to clearly state what knowledge gap their work will fill COMPARED TO the current status on the investigated topic.

Response 1:  

The application of current heat pump technologies in the greenhouse heating has promoted the development of industrialized vegetable planting, but there are still some problems. For example, the heat pump with water as the heat exchange medium has the risk of water leakage and freezing damage of the pipeline. The heat pump is used to heat the whole greenhouse, instead of directly adjusting the temperature of soil/substrate and vegetable rhizosphere, resulting in limited increase of temperature. If the whole space of the greenhouse is heated to a set target temperature, the heat load of the greenhouse is some times of heat needed for vegetable seedling growth. In fact, most of the heat in the upper part of the greenhouse can't be used for the seedling heating, which is wasted in vain. As a result, the equipment investment cost is several times higher than that required for local temperature control. At present, the heat pump technology is difficult to accurately control the temperature and humidity to meet the required conditions of vegetable seedlings at different stages, especially grafting seedlings. The application of heat pump in greenhouse seedling cultivation has not been reported yet. Therefore, a safe, efficient and precise temperature control system with strong adaptability is urgently needed in the greenhouse seedling cultivation in winter.

The MDCRHP with the local temperature and humidity control method was first applied in the vegetable seedling cultivation. It filled the gap of precise control of temperature and humidity in the process of seedling cultivation.

Point2: The uncertainty propagation analysis is missing

Response 2:   

The uncertainties of the test parameters are shown in Table 1.

Table 1 Uncertainties of the test parameters

Parameters	Instrument	Uncertainty	Full scale
Temperature in seedling beds (a-h,A-H)	T-type thermocouple	±0.5 ℃	-50-200 ℃
Relative humidity	Humidity transmitter	±0.5 %	0-100%
Electricity energy consumption	Electricity meter	±0.2 %	¾

 

Point 3：The use of contracted forms needs to be avoided

Response 3:

The unit costs of the electric wire and the thermostat are ¥ 40 /100 m and ¥ 85 respectively, which were presented by Ningbo electric heating equipment factory. Now in order to avoid the use  of contracted form, it is revised as: The unit costs of the electric wire and the thermostat are ¥ 49 /120 m and ¥ 144 respectively, which is presented by Jingdong Mall [41,42].

4[1]. https://item.jd.com/10058677992777.html#crumb-wrap.

42.https://item.jd.com/10056568577518.html?cu=true&utm_source=c.duomai.com&utm_medium=tuiguang&utm_campaign=t_16282_35077704&utm_term=e58b0e08dc9b41d6adc075ea03405419#crumb-wrap.

But the outdoor unit of the heat pump is not a standard unit. The price of the heat pump can not be obtained. So we presented the material cost of 3 HP heat pump given by Zhongguang Electric Appliance Co. Ltd.

We donot find the use of contracted forms of other contents except Section 4.2 in this manuscript.

Point 4：What refrigerant was used?

Response 4:

  The refrigerant is R410A. The system was charged with 2.2 kg R410 refrigerant.

Reviewer 2 Report

The authors have partially edited the article and the quality has improved. I recommend publishing.

Author Response

Response to Reviewer 2 Comments

Dear Reviewer,

Thank you for your useful comments and suggestions on our manuscript, again.

We checked English language and style and revised them. Detailed corrections are listed below point by point. In the revised manuscript, all changes marked in red. If you have any further questions or concerns, please feel free to contact us.

The manuscript has been resubmitted to “Agriculture”. We look forward to your positive response.

Sincerely yours,

Qiu Tu

 

Point: The authors have partially edited the article and the quality has improved. I recommend publishing.

Response: No problem.