Abstract: A control procedure operates an expansion valve of an air conditioning system. The control procedure utilizes a first control procedure to bring a calculated superheat value within a range of a target superheat value, and a second control procedure to cause the calculated superheat value to match the target superheat value. Both the first and second control procedures preferably use Proportional, Integral, Derivative control algorithms.

Abstract: Relatively constant temperatures are maintained in a space by varying the capacity of heating or cooling equipment. A proportional band is used to adjust capacity to compensate for changes in heating or cooling load, and the proportional band is adjusted to bring the actual temperature within the space closer to the set point temperature. Such an adjustment may be made by determining the difference between the present temperature and the set point temperature, and adjusting a floating temperature set point by a percentage (e.g., ten percent) of the difference. Such a process may be repeated, for example, at regular intervals, such as once per minute. As a result, the temperature within the space approaches (e.g., asymptotically) the set point temperature whether the heating or cooling load is high or low. Methods, systems, and apparatuses are contemplated, including HVAC units and controls, including for residential applications, including using variable-speed drives.

Abstract: Compact and efficient apparatuses for transferring heat, heat exchangers, and furnaces, as well as HVAC units, HVAC systems, and buildings therewith, plus methods of making such devices. Furnace heat exchangers, for example, have an added stage, added in an unconventional way, that improves efficiency without unduly increasing size, while maintaining required radiuses of bends in tubing. Various embodiments orient bends at particular angles to allow stages to fit together more closely, provide improved structure for connecting stages using two collectors that seal against a common junction plate, provide for indoor air passing through the heat exchanger to pass through different passes of the heat exchanger in an unconventional order in order to provide greater compactness, or a combination thereof, as examples.

Abstract: Tubing having internal fins projecting inward from the tube wall, each fin having an external surface that includes multiple acute interior angles or crevices that may form nucleation boiling sites, heat exchangers comprising such tubing, and methods of making same. Acute angles, crevices, or elongated slits may be formed in the sides, center, or both, of the fins or between the fins and the tube wall, and convex rounded surfaces may be provided therebetween. Fins may be parallel to the tube centerline or helically wound. Tubing may be expanded with a bullet which may form an interference fit with external fins, may modify the fins to create more effective nucleate boiling cavities, or both.

Abstract: Airflow rates within a ventilation system are controlled using motor speed or torque and motor electric current or pressure. Fan speed or torque may be varied to compensate for differing restriction in ductwork, and may provide a constant airflow rate over a range of varying airflow restriction. Air handlers or air conditioning units may be mass produced in common configurations, and installed in different buildings or structures with different ductwork configurations. Methods operate a fan motor at a present speed or torque, sample speed or torque, sample current of the fan motor or pressure within the ventilation system, calculate a present airflow rate within the ventilation system, calculate a new input setting using the present airflow rate and a target airflow rate, change the speed or torque to the new input setting, and repeat these steps to converge on the target airflow rate, often avoiding overshoot.

Abstract: A blowerless air conditioning or heat pump system for use in providing conditioned air includes an outdoor section that is preferably coupled to an indoor section, and is advantageously used with a forced hot air furnace and a corresponding air distribution duct system of a home or building. The two sections are preferably installed along a boundary of the home or building such that outdoor section is outside of the home and the indoor section is inside or below the home and proximate to a forced hot air furnace. Disposed within the outdoor unit are a compressor, an outdoor coil and an outdoor fan. Disposed within the indoor section is an evaporator coil. There is no separate fan or blower disposed within the indoor section. An inlet air tube couples the indoor section to a first point in the air distribution system, and an outlet air tube couples the indoor section to a second point in the air distribution system. The second point is downstream of the first point relative to the furnace.

Abstract: An improved high-efficiency furnace for use with manufactured housing has a modular heat exchanger assembly having a drum and a plurality of serpentine shaped tubes. A burner extends at least partially into the drum portion of the heat exchanger which acts as a combustion chamber. Hot combustion gases flow upwardly within the drum and enter the tubes heating the drum and tubes. Room air is drawn into the furnace by a circulating blower and blown against the plurality of tubes. The room air is then directed to flow around the drum portion of the heat exchanger where it is further heated before being discharged into the space being heated. The burner includes an inwardly tilted target plate having a plurality of fingers for facilitating the formation of a stable ball of flame within the drum.

Abstract: A heat pump unit for use in small buildings where the unit must be stored in a confined space, not having access to the exterior walls of the building. The unit is contained within a rectangular housing that is divided into three compartments. An outdoor air compartment is vertically disposed between the top and bottom walls at the rear of the housing and an indoor air compartment and a compressor compartment are mounted one over the other at the front of the housing. An outdoor air blower is mounted outside of the housing to save space and is arranged to move air through the outdoor air compartment along a vertical path of travel. An interior vertical wall separates the rear compartment from the two front compartments and contains an upper vertical section and rear wall offset lower vertical section joined by an angularly disposed intermediate section along a vertical path of travel.

Abstract: A single package heat pump unit is field-reconfigurable from a horizontal discharge configuration to a top discharge configuration. A supply panel covers the top and upper part of the back wall, and contains a supply vent in a vent wall, with a blank wall joining it at a ninety degree crease. The supply panel can be removed and installed in the top discharge position, using standard fasteners.

Abstract: Bi-directional fin stock, for use in heat exchangers of the fin and tube type, having louvers formed from the planar surface of the fin stock to project progressively farther into the airstream. This enables the fin stock to exchange heat with a broader airstream by translating the airflow substantially, permitting wider fin spacing.

Abstract: A furnace utilizing, in the upper portion of its cabinet, a blower acting downward through a separator opening to circulate room air past a combustion chamber whose gases flow upward through a sideward-positioned board radiator member which reaches up to the flue. A substantial increase in efficiency results from drawing the combustion gases out of the combustion chamber at the side opposite to the lower end of the broad radiator member, and interposing therebetween, directly beneath the separator opening, a plurality of tubes which serve as an intermediate heat exchanger. A still greater increase in efficiency is achieved by utilizing, instead, a finned tube heat exchanger across and beneath said separator opening; its heat transfer may be so great as to result in condensation of water vapor in the combustion gas. To purge this, a motorized inducer-blower is used in the inlet air system, driving the condensate through the finned tube heat exchanger to an appropriate drain.

Abstract: A self-adjusting, telescoping concentric flue assembly provides non-separating, substantial flexibility between the telescoping sections of both the flue and the air supply ducts. The lower flue and air supply ducts may move radially independently of each other sufficiently to permit installation even on a furnace having somewhat non-concentric flue and air inlet connections. Attachment of the lower air supply duct to the furnace insures that the lower flue is likewise attached, yet the lower air supply duct can be raised independently of the lower flue to check the connection of the latter with the furnace flue connection.

Abstract: A heater and limit switch assembly, particularly useful for installation in the conditioned air duct of a rooftop air conditioner. The loop of a rigid-loop heater, mounted on a vertical plate by two parallel legs, is modified to provide an inward offset portion leading to the second leg. Radiation, from the offset portion and its bend into the second leg, is received at close range by a simple disk-type limit switch, positioned on the plate outward of the second leg and facing the offset, inducing prompt response to any increase over design temperature.

Abstract: A low profile ceiling duct assembly to be used with rooftop air conditioners. The unit combines an octagonal sheet metal ceiling plate which provides the upper portion of a plenum chamber; this extending into the roof space above a ceiling opening. The lower plenum portion is provided by the molded plastic octagonal air distributor box, mounted against the edges of the plate and extending into the room space sufficiently to afford air flow sidewardly outward from the plenum. The air distributor box has outlet grilles at alternate sides of the octagon. They discharge air in four directions along the ceiling line while return air is drawn centrally upward.

Abstract: A fin-and-tube heat exchanger designed for one-way airflow, in which louvers, formed from the fin stock, progressively increase in length from the fin leading edge to its trailing edge. Their end walls channel air into stagnant air spaces behind the tubes. The tube collars may be offset somewhat toward the fin trailing edge, further reducing the stagnant air zones. In those bent heat exchangers in which air flows in from outside the curve, offsetting the collars also lessens the angular convergence of fin trailing edges inside the curve and presents less resistance to airflow.