Heat recovery for livestock barns: options and cautions
Livestock barn heat recovery captures heat from the warm exhaust air that ventilation fans push outside and uses it to pre-warm the cold fresh air coming in. In a cold climate that can cut the fuel needed to keep animals comfortable, but dust, moisture and frost make the equipment choice and the cleaning plan critical.
Why do barns lose so much heat?
Animals give off heat, moisture, carbon dioxide and ammonia, and the ventilation system has to remove them. In a Canadian winter that means a steady flow of warm indoor air leaves while very cold air is drawn in and must be warmed, often by a gas, propane or electric heater. For young animals, hatching and brooding periods, the heat demand is high. The barn loses heat the way a house does, only with much more air exchanged per hour. Our guide on how to lower your heating bill in winter covers the same principle for homes.
How does a barn ventilation heat exchanger work?
Two air streams pass through a core without mixing. Exhaust air gives up heat to the plates or tubes, and the incoming fresh air picks it up. Because the streams stay separate, you recover heat without recirculating dust or gases. The exchanger can be a fixed unit sized to the fans, or part of a ventilation system built for poultry or swine barns. The same idea appears in houses as a heat recovery ventilator, explained in the heat recovery ventilator guide, and the general mechanism is described in what is a heat exchanger.
The recovered fraction depends on the design, the airflow and the outdoor temperature. Ask the supplier for performance data at your design conditions, and be sceptical of one headline number.
What problems should you plan for?
Barn air is far harsher than house air. Plan for these:
- Dust and feathers that foul the core and cut airflow, so look for easy access and washable surfaces.
- Moisture and frost. Warm humid air cooling in the core can condense and freeze in very cold weather, so the design needs a defrost approach.
- Corrosion from ammonia and wash-down water, which affects materials and fans.
- Static pressure. The exchanger adds resistance, so fans and controls have to be matched to it.
A barn that is not ventilated properly risks animal health, so never trade airflow for energy savings. Ask the supplier how the system behaves if a section fails or ices up.
Are there other ways to recover heat on a farm?
Yes. Dairy operations can recover heat from milk cooling to warm wash water, and heat pumps can lift low-grade heat from exhaust air or ground sources for hot water or in-floor heating. Solar air collectors on a south wall can pre-warm ventilation air in daytime, see solar air heating in Canada. Heat pumps are described in air-source versus ground-source heat pumps. At Drake Landing Solar Community, the principle of storing surplus heat for later, as described on the how it works page, is the same one that makes recovered heat worth having.
How do you decide whether it pays?
Start with your fuel use for the barn over a winter and the cost of the heat you buy, then ask installers to estimate savings under your conditions. Include maintenance time, replacement cores and fan power. Prices and savings vary by barn type, region and fuel, so quotes and a detailed estimate decide. Provincial agriculture ministries and the Government of Canada sometimes offer funding for on-farm energy efficiency, and the Alberta farm solar funding guide shows how to look for it. An energy audit of the barn is a good first step.
Quick answers
What is a heat exchanger in a livestock barn?
It is a device that passes warm exhaust air and cold fresh air through a core so the incoming air picks up heat without mixing with the exhaust.
Does heat recovery work in very cold weather?
Yes, but frost can form in the core when humid exhaust air cools. Choose a design with a defrost method, and check how the supplier handles temperatures like yours.
Can heat recovery replace the barn heater?
Usually it reduces the heater's workload rather than replacing it, especially in the coldest weeks or when young animals need extra warmth.
Is there funding for barn heat recovery?
Programs for on-farm energy efficiency come and go and vary by province. Check your provincial agriculture ministry and the Government of Canada energy pages for current terms.