Forced air circulation electric convection space heating system utilizing heated air discharge to preheat air to be heated

摘要

An electric forced circulation space heating system has a first heat exchanger provided with electric heating elements for heating a heat exchange fluid, such as antifreeze or oil, pumped through a closed loop including first flow passages of a second heat exchanger having second flow passages in heat exchange relationship with the first flow passages thereof. A blower forces room air through the second flow passages of the second heat exchanger to be heated by the heated liquid flowing through the first flow passages thereof. A third heat exchanger downstream of the second heat exchanger has first flow passages with an inlet receiving heated air from the second flow passes of the second heat exchanger and an outlet for discharge of the heated air into the space to be heated. The third heat exchanger has second flow passages having an inlet receiving room air to be heated and an outlet connected to the air inlet of the blower, to thereby allow the incoming room air to be preheated by the the heated air flow through the first flow passages of the third heat exchanger prior to discharge into the space to be heated.