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Introduction

When the air flow and the CO₂ gradient measurements are difficult, the animal housing thermal balance makes it possible to estimate the rate of ventilation suitably. The objective is thus to make measurements containing moisture and temperature, even if the ventilation is natural or forced. However, to apply this method it is necessary that the heat produced by the animals model is applied and that other sources (heating, conducting transfer by the walls, are known or negligible).

the principle is identical to the tracing one: one suppose the heat fluxes are known, that the ventilation explains the relation between heat production and temperature variation (or enthalpy, or steam), and one deduce that the ventilation rate equalizes the report/ratio of the temperature variation by the production of heat leaving by ventilation.

Equipment

Moisture and temperature are measured inside and outside the house. Given the high sensitivity of the ventilation deduced from the latent heat production to the steam gradient, it is very important that the moisture sensors are correctly maintained and calibrated.

In addition an estimate of the weight and the production (growth) of the animals is necessary. The result is not very sensitive to this input. Consequently if a measurement is preferable, what the farmer says is often sufficient.

Guideline details

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