Boiler

A central hot water boiler is one of the most common ways to provide heating in the greenhouse. It uses a fuel, such as natural gas and a heat exchanger, to heat up the water of the heating system. When burning fossile fuels, the produced flue gas contains high concentrations of CO2 and sensible and latent heat that can be used for CO2 fertilisation (if clean enough) and/or to heat up the greenhouse using a flue gas condensor in combination to a low temperature heating system.

Contribution to energy balance and resource use of greenhouses:

The boiler heats up the greenhouse adding energy to it.

The CO₂ from the flue gas can be harvested and injected into the greenhouse.

Possible steps towards sustainable, energy-efficient greenhouses

Biomass boilers may be more sustainable than fossil-fuel based boilers. However, a bigger contribution to sustainability can be made by meeting the heating demand in the greenhouse partly or entirely by renewable heating such as through heat pumps, and using boilers only as the last resort.