Greenhouse CO Enrichment Calculator

Estimate greenhouse CO₂ dosing from air volume and crop losses

Greenhouse CO₂ enrichment is not just a matter of selecting a ppm setpoint and opening an injector. Before the crop benefits, the air volume must be raised from its ambient concentration to the target. After that initial fill, plants remove carbon dioxide during photosynthesis while leaks, openings, and ventilation replace enriched air with lower-CO₂ air. This calculator treats those as separate planning needs: the initial kilograms needed to raise the greenhouse concentration, followed by the hourly and daily kilograms needed to replenish leakage and plant uptake. It also converts the 24-hour estimate into a daily gas cost using the price entered in the form.

This greenhouse CO₂ calculator is useful when comparing targets such as 800, 900, or 1,000 ppm against the size and tightness of a particular house. A large but well-sealed greenhouse may need relatively little leakage replacement, while a drafty structure or a crop with high uptake can require considerably more gas per hour. Expressing the assumptions as kilograms and daily cost can help with injector capacity, supply planning, and budget comparisons before committing to cylinders, combustion equipment, or bulk CO₂.

Greenhouse CO₂ inputs: volume, ppm gap, leakage, and uptake

For greenhouse CO₂ calculations, floor area and ceiling height set the air volume. Concentration in ppm is not a mass on its own, so a larger air volume needs more CO₂ to make the same ppm increase. Where roof heights vary, enter an average interior height that represents the air space being enriched. A highly precise survey is not necessary for planning, but a major volume error changes the fill estimate directly.

Target CO₂ is the desired concentration, and ambient CO₂ is the concentration of the starting or incoming air. The calculation uses the difference between those values. A small target-to-ambient gap produces a smaller initial fill and smaller leakage-related loss; a much higher target produces more of both. The form does not assume a universal ambient reading, so use a baseline that suits the greenhouse conditions you are evaluating.

Leakage rate is entered as the percent of greenhouse volume lost each hour. In this model, leakage acts on the enriched portion above ambient, which means a wider ppm gap carries a larger leakage mass. Construction quality, door use, vents, and weather can all make this input uncertain. Because it is a percentage of volume, the same leakage rate corresponds to more kilograms per hour in a larger greenhouse.

Plant uptake represents crop CO₂ removal in grams per square meter of floor area per hour. It is a simplified planning input rather than a fixed crop property: light, canopy size, temperature, cultivar, water status, and nutrition affect actual photosynthesis. The calculator converts that area-based rate to kilograms per hour across the entered floor area. CO₂ price then converts the calculated 24-hour gas demand to a daily cost.

For a greenhouse CO₂ plan with uncertain losses, run more than one case instead of relying on a single precise-looking result. Try a higher leakage or uptake rate for a cautious estimate and lower losses for a favorable estimate. The range can be more useful for operating decisions than an unsupported single assumption.

Greenhouse CO₂ equations used by the calculator

The greenhouse CO₂ model first calculates volume, converts the concentration increase from ppm to a fraction, and multiplies by air volume and the script’s CO₂ density constant. It then adds the leakage mass and crop-uptake mass to obtain hourly replenishment. The daily requirement is that hourly result multiplied by 24, and daily cost is the daily mass multiplied by the entered price.

For this greenhouse CO₂ calculation, the script uses ρ = 1.98 kg/m³. Leakage is calculated from the concentration increase above ambient, greenhouse volume, density, and the entered hourly leakage fraction. Plant uptake is converted from grams per square meter per hour to kilograms per hour using floor area. The displayed daily result assumes 24 hours of maintenance. If dosing occurs only during selected light hours, use the hourly replenishment value to scale gas use to the intended operating schedule.

The greenhouse CO₂ page also displays an estimated yield-increase percentage based on the entered ppm difference. Treat that output as a simple heuristic rather than a crop-performance guarantee. Actual response depends on whether light, temperature, irrigation, nutrition, cultivar, and other climate conditions allow the crop to use additional CO₂.

Default greenhouse CO₂ enrichment example

Using the default greenhouse CO₂ inputs gives a concrete view of how the model works: 500 m² of floor area, 4 m of height, 800 ppm target CO₂, 420 ppm ambient CO₂, 10% hourly leakage, 0.8 g/m²/hr plant uptake, and a price of $0.50 per kilogram. The greenhouse volume is 2,000 m³, and the enrichment gap is 380 ppm. With the density used by the script, raising that volume by 380 ppm requires about 1.50 kg of CO₂ as the initial fill.

For those default greenhouse CO₂ assumptions, leakage of the enriched portion is about 0.15 kg per hour and plant uptake is 0.40 kg per hour. The combined replenishment rate is therefore about 0.55 kg per hour. Over the calculator’s 24-hour maintenance period, that is about 13.21 kg of CO₂; at $0.50 per kilogram, the displayed daily cost is about $6.61. The script’s yield heuristic reports 28.5%, but that percentage should not be read as a predicted harvest result.

This greenhouse CO₂ example distinguishes start-up gas from operating gas. The initial fill applies when concentration is brought up from ambient. The hourly replenishment rate is the more relevant operating figure once dosing is underway, and it can be multiplied by the actual number of enrichment hours when a 24-hour schedule is not appropriate.

Reading greenhouse CO₂ fill and replenishment results

The greenhouse CO₂ result table has six outputs with different uses. Volume checks the size calculation. Initial CO₂ needed estimates the mass required for a one-time rise from ambient to target. Hourly CO₂ replenishment combines modeled leakage and crop demand. Daily CO₂ requirement applies the page’s 24-hour assumption. Daily cost prices that gas demand. Estimated yield increase is only the script’s simplified response indicator, not a guarantee of crop output.

When reviewing a greenhouse CO₂ scenario, adjust one field at a time and check whether the direction makes sense. Increasing the target ppm increases the initial fill. Increasing leakage increases hourly replenishment. Increasing crop uptake increases hourly replenishment even when greenhouse volume is unchanged. Unexpected movement can point to a source-data unit error.

For greenhouse CO₂ enrichment, a target below ambient produces a negative ppm difference in the form calculation. That mathematically indicates that no added CO₂ is needed to reach that lower target, but it is generally not a practical enrichment case. Use a target at or above ambient when planning dosing.

Greenhouse CO₂ planning assumptions and checks

This greenhouse CO₂ calculator assumes reasonably mixed air, steady crop uptake, steady leakage, and a fixed density conversion. Actual greenhouse conditions change with fan operation, vent position, solar radiation, weather, and crop activity. Use the outputs to compare consistently defined scenarios and identify important inputs, rather than as an exact gas invoice.

Three greenhouse CO₂ checks are especially useful. First, compare hourly replenishment with the capacity of the injection equipment; a system that cannot supply the modeled top-up rate may not maintain the target. Second, compare the displayed 24-hour demand with the planned enrichment window, since dosing only during daylight requires fewer hours than the default daily calculation. Third, rerun the estimate with more than one gas price when supply, handling, and delivery costs are uncertain.

Finally, greenhouse CO₂ response is conditional on the rest of the crop environment. When light, temperature, irrigation, and nutrients are limiting, added CO₂ may not deliver the growth response suggested by a simple ppm-based heuristic. Use the result panel alongside wider climate and crop-management information.