The Principles
The principle of the heat exchanger is based on the transfer of heat by conduction. Heat must be transferred through a wall with the intend for heat recovery. With a Plettenburg heat exchanger it is possible to heat or cool 100% fresh outside air. This results in an optimal climate in the shed. The fresh outside air is heated by exhausted shed air aiming to get the highest efficiency on heat recovering. The fresh outside air passes through a packages of tubes and is heated by the exhausted warm shed air in cross flow or counter flow. The result is a conditioned fresh air with a temperature almost equal to the inside shed temperature. This conditioned air has also a lower humidity and has the maximum capacity to dry. The humid shed air containing CO2 and HN3 is not reused.
the Heat Exchanger In Operation
The heat exchangers can be installed either inside or outside the barn. For both options the shape and dimensions were chosen carefully to get the optimal heat recovery. The centrifugal fan moves the outside air. The outside air passes through a stainless steel filter, through the inside of the plastic tubes towards the end of the heat exchanger. During its transportation through the system the air is heated or cooled. When the outside air needs to be heated, the axial flow fans exhaust the warm shed air along the outside of the plastic tubes. During the summer the hot outside air is cooled by means of sprinklers, which can spay (ground)water over the plastic tubes.
1) GAUZE FILTER: The outside air is aspirated through a stainless steel gauze filter. The stainless steel gauze is mounted in pocketfilter frames of galvanized steel. This filter prevents a rapid filthiness of the heat exchanger. The surface of the filter is easily cleaned with a high-pressure water sprayer or a brush.
2) FAN SECTION: The fresh outside air is moved by double inlet centrifugal fans. The fans have high efficiencies and accordingly, good working economy. The fan unit, consisting of fan, motor, V-belt drive and base frame, is supported on antivibration mountings. The outlet flange of the fan is connected to the outlet opening of the fan section by a flexible connection to prevent transmission of fan vibration to the unit. The fan section can be placed in front or behind the heat exchanging section.
3) AXIAL FLOW FAN: The warm saturated air is exhausted by one or more axial flow fans. Depending on the construction of the heat exchanger the axial flow fans can be mounted on the roof or through the ridge wall of the shed. In the outdoor heat exchanger the axial flow fans are situated in the roof construction of the unit Itself. The axial flow fans are selected on high efficiency and lowsound level. The warm saturated air is aspirated into the heat exchanger in the front on upper-side or lower side. The saturated air leafs the heat exchanging section at the end, and is blown out through a chimney.
4) The long heat exchanging section varies from 7 to 10 meter length and contains plastic tubes. The exchanger contains a large heat exchanging Surface and a high efficiency