Work out the phase-change-material melting point, quantity, and panel count to hold an insulated box at a target temperature for a set duration.
Don't know your numbers yet? Find your product below for the internal temperature to aim for and the PCM melting point to buy or set — then use these as your starting point in the calculator below.
| Product | Internal temperature to hold | PCM melting point to use | Why |
|---|---|---|---|
| Fruits & vegetables | |||
| Chill-tolerant fruit & veg (apple, potato, cabbage, carrot) | 2–8°C | 0 to −1°C | Tolerates cold well; a few degrees of headroom is safe. |
| Lettuce | 0°C | −2°C | Very low chilling risk, but highly ethylene-sensitive — keep away from banana/mango/avocado/tomato. |
| Water greens / kangkong | 0–1°C | −2°C | Handle like other high-moisture leafy greens. |
| Cassava leaves | 0–2°C | −2°C | Short storage life (10–14 days) even when well cooled — move it quickly. |
| Leafy vegetables (spinach, coriander, methi) | 0–4°C | −1 to −2°C | High respiration and moisture loss — cold and steady is safest. |
| Broccoli | 0–2°C | −1 to −2°C | One of the highest respiration rates of any vegetable — cool it fast and keep it near 0°C. |
| Avocado (Hass) | 3–7°C | 1–5°C | Chilling-sensitive below ~3°C; high ethylene producer. |
| Cucumber | 3–7°C | 1–5°C | Chilling-sensitive — don't cool as hard as hardy vegetables. |
| Hot peppers / chillies | 5–10°C | 3–8°C | Moderately chilling-sensitive. |
| Capsicum / bell pepper | 7–10°C | 5–6°C | Chilling-sensitive — colder than ~7°C causes pitting and decay. |
| Okra | 7–10°C | 5–8°C | Chilling-sensitive and short-lived (7–10 days) even when handled well. |
| Tomato (firm ripe) | 8–10°C | 6–8°C | Narrow window — chilling-sensitive below ~8°C. |
| Pineapple | 7–13°C | 5–11°C | Low ethylene sensitivity, travels well with other produce; still avoid over-chilling. |
| Eggplant | 10–12°C | 8–10°C | Chilling-sensitive — pitting develops below ~10°C. |
| Banana | 10–13°C | 8–11°C | Very chilling- and ethylene-sensitive — keep away from other ripening fruit. |
| Plantain | 10–13°C | 8–11°C | Same handling as banana. |
| Chilling-sensitive fruit & veg — other/unlisted | 10–15°C | 8–13°C | Keep the PCM melting point close to target, not far below it, until you know the specific commodity's limit. |
| Watermelon | 10–15°C | 8–13°C | Very low respiration, but highly ethylene-sensitive. |
| Mango | 13°C | 11.5°C | One of the narrowest safe windows here — chilling injury below ~13°C for many varieties. |
| Custard apple / sitaphal — whole fresh fruit | 15–20°C | 13–15°C | Very chilling-sensitive; injury sets in below ~15°C — a cool-room job, not a fridge job. |
| Fruit pulp / purée | |||
| Fruit pulp / purée, chilled (mango, sitaphal, guava, etc.) | 0–4°C | −1 to −3°C | Already processed — no living-tissue chilling injury to worry about. |
| Fruit pulp / purée, frozen (mango, custard apple/sitaphal, guava, etc.) | −18°C | −20°C | Panel needs to sit colder than target so it still has pull left as things settle. |
| Seafood & meat | |||
| Seafood / fish, fresh iced | 0–2°C | 0°C | As close to 0°C as possible without ever freezing the flesh. |
| Processed fishery products | 0–4°C | 1°C | Being processed doesn't relax the temperature discipline. |
| Seafood / fish, frozen | ≤ −18°C | −20°C | Same headroom logic as frozen pulp. |
| Live bivalve molluscs (oysters, mussels, clams) | 4–8°C | 4°C | Must stay alive — both overheating and hard freezing kill them; keep melting point above 0°C. |
| Meat & poultry, fresh chilled | 0–4°C | 0°C | Needs to stay just above freezing, not below it. |
| Meat & poultry, frozen | ≤ −18°C | −20°C | Same headroom logic as above. |
| Dairy & soy | |||
| Dairy products (general) | 2–6°C | 0 to −2°C | Little tolerance for time spent above target. |
| Milk (raw / pasteurised, liquid) | 4°C | 2°C | Standard bulk raw-milk chilling temperature; sours fastest of anything here if left warm. |
| Paneer (fresh, in water/vacuum pack) | 4–6°C | 1–2°C | High moisture — turns slimy fast on any warm-up, keep continuously cold. |
| Milk-based sweets (khoya/paneer mithai, syrup-based) | 4–8°C | 1–3°C | Sugar syrup and khoya support microbial growth quickly at room temperature. |
| Tofu (packed in water) | 1–4°C | −2 to −1°C | Sits in its own water — if the water warms, the tofu warms with it. |
| Other cold chain | |||
| Pharmaceuticals (e.g. vaccines) — not food | 2–8°C | 3°C | Freezing destroys many vaccines as surely as overheating — never let the melting point near 0°C. |
Ethylene note: high-ethylene producers (avocado, banana, mango, tomato, plantain) speed up ripening and spoilage in ethylene-sensitive produce (lettuce, watermelon, cucumber, leafy greens) if packed together in the same sealed box — keep them apart where you can.
General rule behind every row: set the PCM melting point 2–3°C below the temperature you want inside for anything above freezing, and a little more (2–4°C) below target for frozen goods, so the panel still has "cooling power in reserve" right up to the end of the trip — rather than just barely reaching your target and then failing immediately.
Product
Target & environment
Insulated box
PCM panels
Across published comparisons, water and water–glycol mixes have the highest latent heat and the best value per kg of any PCM — but they only cover melting points from about 0°C down to −3°C. For anything colder or warmer than that, you need an organic/paraffin or salt-based PCM, which costs more for the same cooling capacity.
| Wall transmission (insulation gain) | – |
| Product pull-down (sensible heat) | – |
| Respiration heat (fresh produce only) | – |
| Total load, with safety margin | – |