A heater assembly to be located at a substantially vertical wall for heating air. The heater assembly includes one or more heating elements, and one or more heat transfer elements mounted on the heating element for transferring heat to a column of the air moving substantially upwardly past the heat transfer elements. The column includes an inner portion positioned proximal to the wall and an outer portion positioned distal to the wall. Each heat transfer element is formed to transfer substantially more heat to the outer portion of the column of the air than to the inner portion thereof, to cause the outer portion to rise faster than the inner portion, for at least partially entraining the inner portion with the outer portion, so that at least a part of the inner portion forms a laminar boundary layer flowing along the wall.

A heating control system including an air circulation fan, a heating unit, a memory, and a microprocessor. The microprocessor is configured to operate the air circulation fan at a first speed and the heating unit in a first configuration to achieve a first temperature rise where less than all of the burners are active. The microprocessor is further configured to compare the first temperature rise to a first temperature rise threshold and transition the air circulation fan to a second speed to achieve a second temperature rise when the first temperature rise is less than the first temperature rise threshold. The microprocessor is further configured to compare the second temperature rise to a second temperature rise threshold and transition the air circulation fan to a third speed when the second temperature rise is greater than the second temperature rise threshold.

A greenhouse, for cold weather climates, is configured with a gable that is offset toward the north wall and therefore the south extension of the roof, from the gable to the south wall is longer than the north extension. A greater amount of light can enter through this south extension and the inside surface of the north wall is configured with a reflective surface to allow light to be more uniformly distributed around the plants. The north wall may have no widows and may be thermally insulated to prevent the greenhouse from getting too cold during the night. A ground to air heat transfer (GAHT) system may be configured to produce a flow of greenhouse air under the greenhouse for heat transfer, to moderate the temperature of the greenhouse. A thermal medium may flow to a thermal reservoir for heat exchange with the conduits of the GAHT system.

A combination boiler provides heated water to a boiler loop and heated domestic hot water (DHW) to a DHW loop. A primary heat exchanger is connected to the boiler loop. A burner provides heat to the primary heat exchanger and an input fan supplies a fuel and air mixture to the burner. A secondary heat exchanger transfers heat energy from the boiler loop to a domestic water loop. A controller determines a boiler loop flow rate. The controller measures an input temperature of the boiler loop, an output temperature of the boiler loop, and a DHW output temperature of the domestic water loop. The controller determines a DHW input temperature and estimates a DHW flow rate. The input fan speed is initiated or operated according to a required heat output of the burner corresponding to the DHW flow rate.

A combination boiler provides heated water to a boiler loop and domestic hot water (DHW) to a domestic water loop. The combination boiler includes a primary heat exchanger (PHE) connected to the boiler loop and a burner to provide heat to the primary heat exchanger. A secondary heat exchanger (SHE) transfers heat energy from the boiler loop to the domestic water loop. A controller monitors a PHE inlet temperature and a DHW output temperature, obtains a pre-heat initialization temperature threshold and a pre-heat cancellation temperature threshold, and detects a low temperature condition. A pre-heat operation is initiated responsive to the low temperature condition by circulating heated water from the PHE to the SHE. The burner is selectively fired at least in part according to an outlet temperature of the PHE.

The present invention relates to a combined fuel cell and boiler system, and comprising: a fuel cell portion for receiving supplied outside air and raw material gas and generating electricity through a catalyst reaction; and a boiler portion comprising a latent heat exchanger, which is connected to an exhaust gas pipe of the fuel cell portion, for collecting the latent heat of self-generated exhaust gas with the latent heat of exhaust gas from the fuel cell portion. The present invention can effectively increase the efficiency of a boiler by supplying the exhaust gas from the fuel cell to the latent heat exchanger in the boiler, so as to be heat-exchanged in the latent heat exchanger with the exhaust gas from the boiler and then discharged, and can simplify the composition by unifying exhaust gas pipes.

A cold water intake pipe 4 and a hot water extraction pipe 5 that communicate with multiple spiral tubes 101 and a steam supplying pipe 2 and a condensate discharge pipe 3 that communicate with a shell are connected to a corrugated spiral tube type heat exchanger 1. Between the cold water intake pipe 4 and multiple spiral tubes 101, communication paths 46 that communicate between the cold water intake pipe 4 and some multiple spiral tubes 101a are provided, and a valve 44 is provided to communicate between the cold water intake pipe 4 and the other multiple spiral tubes 101b when the force acting from the cold water intake pipe 4 becomes larger than the force acting from the other multiple spiral tubes 101b and to block the cold water intake pipe 4 from the other multiple spiral tubes 101b when the force acting from the cold water intake pipe 4 becomes smaller than the force acting from the other multiple spiral tubes 101b.

A storage type gas water heater has two or more tanks/areas providing a primary heated water storage area from which hot water is drawn, and one or more supplementary water storage areas utilizing hot combustion gas from the primary heated water storage area generating and supplying temperate water to previous supplementary water storage areas and/or the primary water storage area. An energy recovery chamber is situated between the primary heated water storage water area and the supplementary water storage area(s), with combustion gas vented therein. A hollow diffuser, defining a diffuser cavity, or one of various heat exchangers, is provided in the energy recovery chamber over the vented combustion gas. The diffuser cavity or heat exchanger receives temperate water from the supplemental water storage area and further heated by the vented combustion gas impinging the hollow diffuser or heat exchanger before being provided to the primary water storage area.

A heating control system including an air circulation fan, a heating unit, a memory, and a microprocessor. The microprocessor is configured to operate the air circulation fan at a first speed and the heating unit in a first configuration to achieve a first temperature rise where less than all of the burners are active. The microprocessor is further configured to compare the first temperature rise to a first temperature rise threshold and transition the air circulation fan to a second speed to achieve a second temperature rise when the first temperature rise is less than the first temperature rise threshold. The microprocessor is further configured to compare the second temperature rise to a second temperature rise threshold and transition the air circulation fan to a third speed when the second temperature rise is greater than the second temperature rise threshold.

The invention relates to a floor drain comprising a drain compartment having a bottom, at least one side and an open upper portion. The bottom and the at least one side together define a space to collect waste water. The bottom comprises an opening for a drain trap. The floor drain further comprises a heat exchanger element, receivable in the space of the drain compartment, for transferring heat present in the waste water to fresh water. The heat exchanger element is provided with a first connection and a second connection. The first connection and the second connection are arranged inside the space of the drain compartment. A first conduit is connected to the first connection and a second conduit is connected to the second connection.