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Orugbo Studio

Cold room sizing calculator

A working example of what we build for cold storage and refrigeration companies. Built on the ASHRAE load calculation method.

Your room

Length, width and height. Any size, not only standard ones.

degrees C

kg arriving each day

Powering it with solar

the battery must carry

affects inverter size

Refrigeration capacity required
16.3kW
55,720 BTU/hr · 4.6 tons refrigeration
Room volume
75.0 m³
Holds about
22,500 kg
Insulation
100mm panel
Daily heat load
294 kWh
Email this specification to Orugbo StudioOr send it on WhatsApp

Opens with the whole specification already written out.

Where the load comes from
Cooling and freezing the product188.4 kWh · 74%
Heat through walls and ceiling21.7 kWh · 8%
Air infiltration through the door15.9 kWh · 6%
Evaporator fans14.1 kWh · 6%
Defrost7.0 kWh · 3%
Heat through floor5.3 kWh · 2%
People working in the room2.6 kWh · 1%
Lighting0.6 kWh · 0%

Calculated to the ASHRAE refrigeration standard, with a design margin, over 18 running hours a day.

Power required to run it
9.4kW electrical
168 kWh per day · 61,497 kWh per year

At -18°C against a 30°C ambient the plant runs at a COP of 1.74, so each kW of cooling costs about 0.57 kW of electricity.

Solar system to run it · United Kingdom
Solar array
83.1 kWp
128 × 650 W panels
Roof area
396 m²
Battery
105 kWh
84 kWh usable
Inverter
12 kW
33 kW starting surge
  • At -18°C the plant achieves a COP of only 1.74, so every kilowatt of cooling costs about 0.57 kW of electricity. Freezing is expensive to run, which is what makes solar worth costing properly.
  • Sized for a direct on line compressor, so the inverter must survive a 33 kW starting surge. A soft starter would bring that down to about 17 kW and can meaningfully reduce the inverter you need to buy.
  • United Kingdom averages only 2.6 peak sun hours, so the array carries most of the cost here. A grid tied system with battery backup usually works out better than going fully off grid.

What this tells you

Anyone planning a cold room starts with one question: what size of refrigeration do I need? Put in the room, the product and how much arrives each day, and this gives the capacity in kW, BTU per hour and tons of refrigeration.

With solar switched on it also names the array, battery and inverter to run the room, which matters where the grid cannot be trusted with a room full of stock.

Use the answer for budgets and early conversations. A refrigeration engineer still confirms the design before anything is bought.

Have these to hand

  • The inside length, width and height, in feet or metres.
  • What you will store, and the temperature you want to hold it at.
  • How many kilos arrive on a normal day. On a busy day too, if the two are far apart.
  • Where the room will be built, if you want the solar figures.

Reading the result

People tend to size a cold room by its floor area, then get caught out by the daily load. Everything that arrives warm has to be brought down to temperature, so try your busiest day as well as your normal one and see what happens to the duty.

On the solar side, try the days without sun setting and the compressor start. The first moves the battery and the second moves the inverter.

Questions people ask

Why does it matter what I am storing?

A tonne of fish does not behave like a tonne of bottled drinks. Each product has its own storage temperature and its own cooling demand, so the tool asks instead of assuming. It covers 25 products, from beef and shrimp to vaccines and cut flowers.

Can it handle a freezer room as well as a chiller?

Yes. Pick a frozen product or set the storage temperature yourself, and the result changes to suit.

Does it work outside Nigeria?

Yes. The refrigeration figure works anywhere. The solar figures depend on sun hours, and the list covers Nigeria by region, Ghana, Kenya, South Africa, the Gulf, India, the UK, southern Europe, the United States and Australia.

Can I build from this?

No. It is an estimate built on the ASHRAE load method, for planning and for talking to suppliers. Door use, the site and the equipment you choose all need an engineer’s eye.

See all six calculators →

Want this on your own website?

This is the real thing, not a mockup. We build these for cold storage and refrigeration companies and put your own rates inside, so the number a visitor sees is one you would stand behind. It embeds in the site you already have with one line of code, or sits on a subdomain with a single DNS record. We never need access to your hosting.

Fixed price, fixed date, agreed in writing before anything starts. Tell us what people ask you before they buy and we will say honestly whether this is worth doing for you.