Solar for cold storage in Bangladesh: compressor duty, roof and backup needs

By Vvon Engineering Team | Published 2025-12-23 | Updated 2026-09-13

How seasonal compressor duty, product-temperature requirements and insulated-roof details affect cold-storage solar and backup design.

Solar EPC & street lighting RFQ checklist (TXT)

Cold storage and food processing can have substantial refrigeration demand, but compressor duty follows stock, ambient conditions, loading and controls. Assess both energy savings and the product-temperature consequences of an interruption.

A load that never reaches zero

Log compressors, fans and pumps over representative loading and operating periods. Continuous temperature control does not mean every compressor runs continuously or that all PV is self-consumed.

Model the seasonal generation and refrigeration profiles together. Hot weather, cloud, product arrival and shutdowns can change the overlap. Confirm capacity and export conditions with the utility.

Input	Evidence needed	Why it matters
Consumption	Twelve months of bills and representative interval demand	Separates direct use, exports and changing demand.
Generation	Location, layout, weather dataset and loss assumptions	Estimates output month by month.
Connection	Sanctioned load, transformer and utility requirements	Establishes eligible capacity and approval conditions.
Installed cost	Dated itemised quotation and exclusions	Includes roof work, connection and commissioning.
Operating cost	Maintenance, insurance and replacement assumptions	Avoids treating later electricity as cost-free.

Survey the actual usable roof around refrigeration plant, walkways and shading. Storage tonnage does not establish roof capacity or the right PV size.

Backup that protects the stock, not the lights

Storage may support defined refrigeration loads during an outage if its power, starting capability, energy and controls meet the required duty. No fixed number of backup hours follows from adding a battery. Compare it with generator and thermal-management alternatives.

The design question is which compressors sit on the protected bus. Carrying every machine in the plant room through a four-hour outage is a large and expensive battery. Carrying enough refrigeration capacity to hold chamber temperature within its allowable band, with the loading bay and the office deliberately left out, is a much smaller one. Have the plant engineer state the permitted temperature rise and the duration it must be held for before anyone quotes kWh of storage.

The roof over a cold store

Have the roof designer assess structural capacity, insulation, vapour control and waterproofing. Use a mounting detail approved for the specific roof system; a non-penetrating clamp is suitable only where the roof profile and load path permit it.

• Condenser decks. Air-cooled condensers are usually on the roof, and they throw both shade and hot air. Modules sitting in a condenser's discharge run hotter and produce less, so the array layout has to be planned around the plant, not fitted between it.
• Ammonia. On plants using ammonia refrigerant, leaks near the plant room attack copper and some coatings. Keep combiner boxes, cable routes and earthing away from the plant room vent path.
• Dust from produce handling. Potato and onion stores generate a persistent fine dust around the loading bays that settles on glass. Set the cleaning interval from the site, not from a generic schedule.
• Harmonic distortion from compressor drives. Large variable frequency drives can distort the supply enough to nuisance-trip an inverter. Measure power quality at the main panel before the design is fixed, not after the plant is energised.

What to ask before you sign

• Show me the mounting detail for an insulated panel roof. If the answer is a self-drilling screw and a washer, ask what happens to the insulation in year five.
• What performance ratio are you guaranteeing, and what is the consequence of missing it?
• Which loads are on the battery bus, and for how long? The answer should be a schedule of compressors and a stated hold time, not a single kWh figure.
• Are the structural certificate, surge protection, earthing and the utility application inside the contract price? A missing or unsigned structural certificate is a routine cause of an application being sent back.
• Who cleans the array, how often, and is it in the O and M contract?

Sources and project checks

Consult the relevant edition and the documents for the exact equipment and site: SREDA: Net Metering Guidelines and current application documents; US Department of Energy: battery energy storage procurement checklist; IEA PVPS: operation and maintenance in different climates; IEC 62548-1: PV array design requirements.

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