Space Heat, Floor Heat and drying out

Space heating

In some cooler areas of the world you require a space heating system. The demand for heating systems is less as you introduce canopies and partly slatted floors.

When you lower the ambient temperature in a room consequently the demand for heat also lowers, but even more. To explain this you must realize that heat demand is governed by the minimum ventilation settings (air quality). The air quality is affected by the production of odour, moisture and ammonia from slats and slurry.

The production depends heavily on the temperature. One degree lower slurry temperature reduces ammonia production by 10 % (source Danish Environmental Agency). The same source states that two third of the ammonia originates from the slurry; the rest comes from the slats. Because both slats and slurry gets cooler when you lower the ambient temperature you can predict 15 % lower ammonia production for each degree lower temperature.

Some examples explain the importance:

1. A farrowing room gets canopies and intelligent heat lamps. The ambient temperature can be set four degree lower. The ammonia production is 48 % lower, and the minimum ventilation is reduced by half. In many places you can leave a space heater out.

2. A weaner room gets intelligent canopies. The ambient temperature can be set eight degree lower. The ammonia production is 72 % lower, and the minimum ventilation is correspondingly lower. In many places you can leave a space heater out.

3. A room gets carbon dioxide controlled minimum ventilation. This assures very precise animal behaviour dependent minimum ventilation. You will not risk excess ventilation in cases where the demand and consequently the heat from the animals is lower. You may omit the space heating system, or as a minimum you will manage with a smaller system.  

Two pre-weaner (4 to 7 kg) rooms in Finland with intelligent canopies have no floor and space heaters.

The two rooms were designed with additional floor and space heaters, but for some reason they never got the two heating systems coupled to the hot water supply. Nobody noticed it during the winter. Early summer they realized that they had gone through the winter with the heating lamps at the canopies only. At no time they had lacked heat and the piglets performed well. The pipes for space heating have now been moved to another room.

A heating system must be in concert with the ventilation system. 


Requirements of a heating system

  • Supplies heat where animals are resting.
  • Equal distribution within the room.
  • Heat must be infinitely variable 0-10 Volt or time modulated with a relay.
  • Must stand the aggressive environment in the room.
  • Easy to clean.

A heating system is not cheap, especially if it is based upon hot water. It also demands feeding the room with hot water and the boiler with chimney, fuel storage and fire protection.

Some countries and states give subsidies to transformation from fossil energy (oil, coal, gas) to renewable energy (biogas, biomass). It may look as an attractive project because the fuel seems cheaper. You have, however, no energy savings. And the whole globe is going to do this so biomass is likely to be very expensive in the future.  

You are better off focusing on exploring the free heat from the animals fully before you start to buy any heat. The above examples make this clear.

VengSystem does not supply systems for floor and space heating, so our advising is fully neutral. We can, however, deliver the heat control equipment (motor valves) for controlling the heat.

Floor heat

Many farmers have floor heat; some also want to use floor heat as a space heater.

It must be pointed out that you cannot use floor heat as a space heater. A space heating system must heat the air, not the animals. When animals have a warm and a cold side stress is generated in the bodies, which affect the production level negatively. Floor heat is good for drying out a floor, but with animals in the pen you better turn it off.

Floor heat takes heat away from the animals with most heat demand. When you have some smaller pigs going in a pen, which have a higher body (surface) temperature, they will deliver heat to the other pens with bigger pigs. This phenomenon is not generally realized. Individual heat per pen is preferred.

Drying out

After washing a room it must be dried out. Start of a batch of pigs at a wet floor equal to a cold floor costs a couple of day’s growth. Drying out can be done by heating and ventilation at the same time or usage of a dehumidifier and no ventilation. The latter takes less energy but takes much more time and the equipment is much more expensive.

When heat is used do not use space heater alone. The heat capacity is far too low, it takes too much time. Use a mobile heater with high capacity. An oil blow heater is recommended as it also circulates the air, which assists evaporation of water at the floor and slats.

Keeping the temperature at 30° removes the double amount of water per unit of air going through the room compared to keep 20°. The water content of the air flowing through is just a few percentages, so it pays off to keep air flow down and temperature up.



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