A non-pressurized tank is a much more cost-effective solution for most commercial solar heating systems. Because there is no pressure a non-pressurized tank only needs to be constructed to hold the weight of the water. This means a much cheaper means of construction.
A non-pressurized tank is typically built on site and comes as a knock down DIY kit. This greatly decreases the transportation cost and also allow the tank to fit through most commercial doors.
The insulation value of a non-pressurized tank is important and should be considered when choosing a tank. Our non pressurized commercial tanks come in insulation values allowing a heat loss of less than 2 degrees per day.
A non-pressurized tank is not suitable for direct potable water consumption. The water in the tank is only used as an energy store and this energy is moved into and out of the tank via pumps and heat exchangers. If the project requires potable water, then this can still be done effectively with a non-pressurized tank by using an appropriately sized external heat exchanger or a 2nd water tank with an internal heat exchanger.