The greenhouse boiler is selected according to the heat lost from the cover on the coldest night: the cover area × the heat requirement coefficient of the cover × (internal − outdoor temperature), with a safety coefficient of 1.2 on top. The result is mostly determined by the province and the cover: the same 1 acre of greenhouse requires 150,000 kcal/h boiler in Antalya and 325,000 kcal/h in Afyonkarahisar; a double layer of inflated PE or heat curtain reduces the peak load by 27-36%. The wizard uses the method of Çukurova University (Baytorun et al.), the project external temperature of 49 provinces and sun-corrected degree-hour data for 24 provinces; besides the boiler, it also gives the annual heat and fuel.
Which cover and application requires how much heat?
| Drape / application | Typical capacity | Heat or steam (engine) | Fluid |
|---|---|---|---|
| Single layer PE (U 7,0) | 1 acre, Antalya, tomato | peak 137 kW (117,400 kcal/h) · boiler 150,000 kcal/h · 143 MWh per year | hot water 90/70 °C |
| Double Inflated PE (U 5,1) | 1 acre, Antalya | peak 99.4 kW (85,500 kcal/h) · boiler 125,000 kcal/h · 104 MWh per year | hot water 90/70 °C |
| 8 mm double-walled polycarbonate (L 4,6) | 1 acre, Antalya | peak 89.7 kW (77,100 kcal/h) · boiler 100,000 kcal/h · 94 MWh per year | hot water 90/70 °C |
| Single layer PE + heat curtain, closed at peak (U 4,5) | 1 acre, Antalya | peak 87.8 kW (75,500 kcal/h) · boiler 100,000 kcal/h · 116 MWh per year | hot water 90/70 °C |
| Single glazing (L 7,6) | 1 acre, Antalya | peak 148 kW (127,400 kcal/h) · boiler 175,000 kcal/h · 155 MWh per year | hot water 90/70 °C |
| Soil steaming | 500 m²/lot, 6 hours, 25 cm, 15 → 70 °C | ≈ 2,520 kg/h direct steam (≈ 30 kg/m²) | steam 0.5–3 bar g |
How many kcal boilers are needed for 1 acre of greenhouse heating?
For tomatoes in a 1 acre (1,000 m²) single-layer PE tunnel greenhouse in Antalya (16 °C at night, +3 °C outside temperature of the provincial project):
- Peak heat loss: 137 kW = 117,400 kcal/h (137 W/m² base)
- Safe (×1.2) boiler load 164 kW = 140,800 kcal/h → 150,000 kcal/h hot water boiler, 90 °C flow, ≈ 7.3 m³/h circulation
- Fuel at full load: ≈ 18.6 Sm³/h of natural gas
- Annual heat ≈ 143 MWh → ≈ 16,000 m³ of natural gas or ≈ 27 tons of imported coal
- Heating pipe (51 mm black steel, 80/60 °C): ≈ 1,350 m (1.35 m/m²)
The annual heating cost is these quantities multiplied by the current unit price (e.g. 16,000 m³ × m³ of natural gas). The degree-hour method acts as an upper limit; the typical year simulation finds the annual temperature 20–40% lower.
1 acre greenhouse boiler by province
| Province (project external temperature) | Peak heat loss | Boiler load (1.2×) | Wizard recommendation | Annual natural gas |
|---|---|---|---|---|
| Mersin (+3 °C) | 117,400 kcal/h | 140,800 kcal/h | 150,000 kcal/h | ≈ 13.300 m³ |
| Antalya (+3 °C) | 117,400 kcal/h | 140,800 kcal/h | 150,000 kcal/h | ≈ 16.000 m³ |
| Adana (0 °C) | 144,500 kcal/h | 173,300 kcal/h | 175,000 kcal/h | ≈ 15.800 m³ |
| Izmir (0 °C) | 144,500 kcal/h | 173,300 kcal/h | 175,000 kcal/h | ≈ 17.400 m³ |
| Aydın (−3 °C) | 171,500 kcal/h | 205,800 kcal/h | 225,000 kcal/h | ≈ 21.300 m³ |
| Denizli (−6 °C) | 198,600 kcal/h | 238,300 kcal/h | 250,000 kcal/h | ≈ 28.000 m³ |
| Şanlıurfa (−6 °C) | 198,600 kcal/h | 238,300 kcal/h | 250,000 kcal/h | ≈ 24.900 m³ |
| Afyonkarahisar (−12 °C) | 252,800 kcal/h | 303,400 kcal/h | 325,000 kcal/h | ≈ 50.800 m³ |
| Nevsehir (−15 °C) | 279,900 kcal/h | 335,900 kcal/h | 350,000 kcal/h | ≈ 51.900 m³ |
Single layer PE tunnel greenhouse, peel/bottom 1.5, tomato 16 °C. For peppers, cucumbers and eggplants, 18 °C is taken at night; in Antalya, the peak increases from 137 to 158 kW (+15%), the annual heat increases from 143 to 205 MWh.
How does the wizard compare to greenhouses on site?
Published plant data on the Mediterranean and Aegean coasts show a peak heat capacity of 90–115 W/m²: 950 kW (≈ 90 W/m²; Baytorun et al. 2017) in a 10,560 m² PE greenhouse with heat curtain in Antalya, 1.47 MW (≈ 115 W/m²) in a 12,816 m² glass greenhouse in Balçova, Izmir. The 137 W/m² found by the wizard for a 1 acre single-layer PE tunnel is above this, which is a conscious choice: the outside temperature is taken from the official provincial project table used in boiler projects (Antalya +3 °C). This value represents the coldest hours of winter; in the same province, the typical year simulation (ISIGER) finds 91 W/m² for a single layer of PE. The shell/bottom ratio of the small tunnel is also higher than that of large gothic blocks.
In the details section, if you convert the outside temperature source to the MGM 1991–2020 winter average (Antalya +6.6 °C), the peak decreases to 99 W/m², and if you turn the heat curtain off at peak, it decreases to 88 W/m²; both fall within the field range. Read the wizard’s result as a safe upper limit: the most economical way to close the gap is to divide the capacity into two boilers and use a buffer tank.
Example: 20 acres gothic block greenhouse, Antalya
Modern gothic block, single layer PE roof and heat curtain. The curtain was calculated open (conservative) as the peak could occur in the morning hours when the curtain opened.
| Input | Value |
|---|---|
| Greenhouse floor area | 20.000 m² (shell/base 1.38 → cover 27.600 m²) |
| Cover | single layer PE + heat curtain, middle sealing; curtain open on peak (U 7,0) |
| Product / internal temperature | tomatoes, 16 °C at night |
| Province / outside temperature | Antalya, +3 °C (project table) |
| Safety coefficient | 1.2% (line loss and growth share 0%) |
- Peak heat loss 2,512 kW (2,160,000 kcal/h; 126 W/m² base); safely 3,014 kW = 2,592,000 kcal/h
- Hot water boiler recommendation: 2,750,000 kcal/h, flow 90 °C, ≈ 133 m³/h circulation, ≈ 341 Sm³/h natural gas at full load
- If the curtain can be safely closed at peak, the peak is 1,615 kW (81 W/m²) and the recommendation is 1,700,000 kcal/h
- Annual heat ≈ 2,132 MWh (107 kWh/m²) → ≈ 239,000 m³ of natural gas or ≈ 403 t of imported coal
- Pipe rail (51 mm steel, 80/60 °C) ≈ 24,800 m
- Practical layout: 2 boilers (e.g. 2 × 1,400,000 kcal/h) + 100–200 m³ buffer tank (Baytorun et al. 2017)
Greenhouse boiler type, temperature, and pressure
A greenhouse boiler is today a low-pressure hot water boiler: 90/70 °C round trip, pipe rail, under table or vegetation pipes. In greenhouses burning coal, pomace or biomass, stoker boiler and buffer tank are used together; the solid fuel boiler meets at least 80% of the annual energy, the cold night peak is taken by the second boiler with gas or oil fuel. In long-line complexes exceeding 10 MW, a superheated water boiler above 110 °C is preferred. Steam is only required for soil steaming: for 2.5 t/h direct steam, the wizard recommends a 3 t/h, 6 bar class package type or hybrid type steam boiler with deaerator steam; At this size, the economizer reduces fuel. Since it is a campaign job, a mobile boiler or steam generator is also used.
How to calculate greenhouse heating?
U_cs is the coefficient of heat requirement, which includes leakage (single coat PE 7.0 · double coat PE 5.1 · 8 mm PC 4.6 · single PE + curtain 4.5 W/m²K; Haase et al. 2014). The shell/base ratio is 1.5 in the tunnel, decreasing from 1.77 to 1.21 as the area grows in the gothic block. Since the coefficient of safety (Baytorun and Buderus: 1.2–1.3) covers line loss and share, the line loss and growth margin in the greenhouse calculation is 0% by default. HDH is the solar-corrected heating degree-hour (Baytorun et al. 2018).
Use the wizard at the top of the page to calculate with your own greenhouse; Boiler Capacity Calculator for all sectors. You can calculate the fuel cost separately with the boiler fuel consumption tool.
The results of the wizard are predictions to give a preliminary idea; boiler selection should be finalized by on-site exploration and engineering calculation. Contact us for free pre-engineering support.