August Solar E Technology [ ] SOLAR HYBRID COLD STORAGE. A pilot R & D site at Chuadanga sponsored by IDCOL & World Bank

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1 August 2017 Solar E Technology SOLAR HYBRID COLD STORAGE [ ] A pilot R & D site at Chuadanga sponsored by IDCOL & World Bank

2 Executive summary: Bangladesh is one of the largest producer of fruits and vegetables but the availability of fruits and vegetables per capita is significantly low because of Post-harvest loses which account for about 25% to 30% of production. Further, the quality of sizeable quantity of produces also deteriorates the moment it reaches the consumer. This happens because of perishable nature of the products. If consumption is not getting stabilized, the farmers switch over to other crops instead of going for one crop in the subsequent year, and cycle continues. Our farmers continue to remain poor even though they take risk to cultivate high value fruits and vegetables year after year. Introduction of Cold storage / Cold room facility will help them in removing the risk of distress sale and simultaneously will ensure better returns. On the other hand, the fruits, vegetables and flowers have also limited life after harvest. Post-harvest cooling rapidly removes field heat, reduces respiratory - activity, reduce internal water, wilting, slow the growth of microorganism and reduces the production of natural ripening agent i.e. ethylene. Post-harvest cooling also provides marketing flexibility by allowing the grower to sell produce at the most appropriate time. With the financial assistance of World bank and IDCOL, Solar E Technology has embarked on a demo solar hybrid cold storage project at Chuadanga and conducted a comprehensive R & D exercise on cool room temperature & humidity control performance, assessment of shelf life of different vegetables, fruits and flowers, freshness quality of produce after removing from storage. A comprehensive cost benefit was conducted considering a commercial project of storage capacity of 60MT of fresh produce. Payback periods for various financial modelling scenario for both off-grid and on-grid solar hybrid cold storage are presented in this report. This is a crucial time for the Government of Bangladesh and IDCOL to make policies of introducing commercial solar hybrid cold storage. Solar cold storage system schematic

3 Cold storage specification: BASIC DESIGN OF COOL ROOM SN Description Specifications 1 Cool room dimension 5m (L) X 3m (W) X 2.5 (H) 2 Cool room temperature 4 C ±2 C 3 Humidity 85-90% RH 4 Ambient temperature 35 C 5 Storage goods Fresh vegetables, fruits & flower 6 Product storage capacity 2 MT 7 Product entry average temperature 30 C 8 Product incoming rate (loading rate) 50% ( 1000 kg per day) 9 Maximum pull down time 24 hrs/batch 10 Insulation Polystyrene sandwich panel (EPS sandwich board which made of outer layers both sides of pre-painted steel coil and inner layer of polystyrene. 11 Floor 100mm thickness of RCC and top paper board 12 Hinge door 1000mm (W) X 2500mm (H), 1No. 13 Cooling demand 3.76 kw 15 Compressor cooling capacity 6.0 kw at -3 C SST and condensing temperature of 40 C 16 Evaporator cooling capacity 8.64 kw 17 Refrigerant R404A 18 Compressor type Reciprocating

4 Cooling load calculation sheet: Condensing unit specification:

5 Evaporator specification:

6 Photos of solar hybrid cold storage: Front view Side view Photo of rear side view showing evaporator unit and control room entrance

7 Control room Ultrasonic humidifier Solar Inverter Evaporator unit Water vapour generates from humidifier

8 Test set up: Cooling performance was observed during 1) Test 1: Cool room average temperature 4.0 C 2) Test 2: Cool room average temperature 6.0 C 3) Test 3: Cool room average temperature 10.0 C 4) Test 4: Cool room average temperature 2.0 C Relative humidity was set to 90% with 5% hysteresis (RH 85% - 90%) Produce Freshness quality observation: 1) Inspect freshness quality of fresh produce removing from cool room after 14 days of storage. Freshness inspection has taken over 24 hours 2) Inspect freshness quality of fresh produce removing from cool room after 21 days of storage. 3) Inspect freshness quality of fresh produce removing from cool room after 24 days of storage. Cool room temperature chart: Test Result Cooling performance Test3 Daily mean temperature C Test2 Test1 Test1 Test4

9 Test1 Test2 Test 3

10 Test 4 Test 1

11 Cool room relative humidity chart: Daily average ambient temperature chart at project site

12 Test Result Produce freshness quality assessment The freshness quality was done by comprehensive inspection of storage produce removing from cool room after 14 days of storage 21 days of storage 24 days of storage Photo showing the vegetables, fruits and flower after 14 days of storage inside cool room

13 Photo showing quality of freshness removing outside from storage after 14 days kept in solar cold storage. Freshness quality observation for 24 hours after taking from cool room after 14 days After 2 hours After 6 hours After 24 hours

14 After 2 hours After 6 hours After 24 hours After 2 hours After 6 hours After 24 hours After 2 hours

15 After 6 hours After 24 hours After 2 hours After 24 hours After 2 hours After 24 hours After 2 hours After 24 hours After 2 hours After 24 hours

16 Photo showing quality of freshness removing from storage after 21 days kept in solar cold storage.

17 Photo showing quality of freshness removing from storage after 24 days kept in solar cold storage. 24 days 24 days 24 days 24 days 24 days 24 days 24 days

18 Power system: 1) Off-grid solar system 2) Alternative source (main grid and diesel generator) Power system specification: Item Specification Quantity Total capacity Solar Panel 250Wp poly kWp Solar inverter Storage battery Diesel generator 8.0kW hybrid inverter with MPPT controller 130Ah, 12V Hamco solar battery Self-start 5kVA diesel generator 1 8.0kW 36 56kWh 1 5kVA Inverter specification:

19 Power consumption: Cold storage daily power consumption was recorded by power analyser.

20 Power consumption pattern: Compressor cycling Defrost Compressor off Total Energy Consumption (TEC) per day = kw/day (measured via power analyser) Generation mix: As July and August is rainy season and it was found most of the day has low sun shine, rainy and cloudy. There had been 6-10 hours of load shedding every day at project site. In order to monitor continuously and optimize cold storage performance, the priority of electricity supply was set to grid first and at the event of load shedding from solar system. Once cold storage performance is optimised, electricity supply priority has changed to solar first, second grid and diesel generator third. Supply mix for solar hybrid cold storage Supply from solar system Supply from alternative source ( grid & generator) 32% Note: This supply mix is for the month of August and based on complete continuous 4 days (96 hours) data. 68%

21 Cost- benefits analysis: We are making the following initial considerations & assumptions about a commercial project of offgrid solar hybrid system for the exercise of cost-benefit analysis: Considering project size of 100KWp solar panel. With 100KWp solar panels, an expected cold storage of 40kW cooling load can be made. Evaporator and condenser size is estimated to be 50kW and 60kW cooling capacity accordingly. Storage battery total capacity to be 650kWh Produce storage capacity is estimated to be 60MT. Total project cost estimated to be Tk.300 Lac. Estimated revenue Tk.0.2 per kg/day Occupancy 80% Management cost expected to be Tk.1,000,000. Supply mix 70% solar & 30% alternative source (grid & generator) Diesel generator size 20kVA Inflation rate 3%. It is also assumed that the sponsor will provide 15% equity with incurring further loan at 10% interest for 8 years Estimated investment at different financial model scenario (Storage battery based off-grid solar system) Scenario Financial model Equity 15% Loan 55% Grant 30% Equity 15% Loan 45% Grant 40% Equity 15% Loan 35% Grant 50% Equity 15% Loan 25% Grant 60% Investment return, year Attractive model Acceptable model Financial risk

22 As most of the fresh produce trading markets/ bazar have the access of electricity, it is a proposition to analyse the financial viability for a solar hybrid on grid cold storage system (no storage battery). Solar power will be the first priority during day operation and during night operation supply will be from grid and generator. For on-grid solar hybrid cold storage with 40kW cooling load, it is estimated to have 40kWp solar panel. There will be no storage battery requirement. The estimated project cost will be Tk 170 lakh. A CBA analysis of such on-grid solar hybrid cold storage has resulted of investment return as below: Scenario Financial model Equity 20% Loan 80% Grant 00% Equity 15% Loan 65% Grant 20% Equity 15% Loan 55% Grant 30% Equity 15% Loan 45% Grant 40% Equity 15% Loan 35% Grant 50% Investment return, year Attractive model Acceptable model Financial risk Scalability of the project The current solar hybrid cold storage has designed and produced by Solar E Technology is a prototype for a commercial system and this design is based on modular concept. No technical modifications are required when upscaling this system into a large scale commercial system. The current design ensures an expected project life of 20 years. Furthermore, the every effort has been made to ensure a reliable resource supply chain which is a vital factor in commercial production.

23 Social impact of the project The showcase of our pilot solar hybrid cold storage project attains a great success; it garnered positive attention from several NGOs and we anticipate that there will be widespread uptake of this technology when we embark solar hybrid cold storage for commercial use. Several media representatives have already interviewed us and taken video of our R & D project. Shelf life observation Name of Fresh fruits/vegetables/flower Observation period Comment Expected shelf life with regards to Bangladesh climate Apple ( normal & green) 24 days No change in freshness. 2 months Orange/malta 24 days No change in quality 4-5 weeks Green Chilli 24 days Remains fresh and saleable to market 3-4 weeks Cabbage 24 days Slight change in freshness. 2 weeks Potol 24 days Remains fresh and saleable to market 3-4 weeks Kakrol 24 days Slight change in freshness. 2-3 weeks Laou (gourd) 24 days Remains fresh and saleable to market 3-4 weeks Green banana 24 days Colour changed 2 weeks Ladies finger 24 days Colour changed 2 weeks Taro (Kochu) 24 days No change in freshness. 4 month Pumpkin 24 days No change in freshness. 5-6 month Rose flower 24 days Leaf becomes slight dry 2 weeks Night queen flower (Rojonigandha) 24 days Remains fresh and saleable to market 3-4 weeks Marigold flower (Ganda) 24 days Remains fresh and saleable to market 3-4 weeks Potato 24 days No change in freshness. 5-6 month Eggplant (Bagoen) 24 days Slight change in freshness. 3 weeks

24 Conclusion Solar hybrid cold storage for fresh vegetables, fruits and flowers for short term preservation is an innovative and environmentally sustainable alternative which will help the farmers to store their produces and market them at the opportune time. Cold storage performance (temperature & humidity control performance) was monitored for 24 days and found to be very promising. Ultrasonic humidifier maintained relative humidity (85-90%) smoothly via humidity controller which helps to preserve perishable goods longer time. In traditional cold storage in Bangladesh, it is a common practice to spray water manually and as local water has bacteria and helps to increase rotten the perishable goods. Ultrasonic humidifier does not produce any heat while producing steam. It atomises the water particles and kills the bacteria of the water if present. The shelf life and freshness of flower found to be very attractive and as there is huge existing fresh flower supply demand in all major cities in Bangladesh, the introduction of solar hybrid cold storage will bring more business opportunities. One of the key elements for fresh produce preservation is to maintain suitable relative humidity and that is why shelf life for fruits and vegetables in the demo project found more than expected. Based on the experience gained of fruits preservation in demo project, it anticipated that mango and jack fruit can be preserved up to 6-8 weeks. Power supply mix found to be 68% solar and 32% alternative source (grid & generator). The theoretical supply mix for the month of August was estimated to 69%. This has revealed the performance ratio (PR) of solar system is 98.4%.