For a look at the latest advances in the industry, the following is a selection of some recent air conditioning, heating, and refrigeration patents.

U.S. Patent 6,220,566:Increment-ally positionable ball valve.

Inventor: Kent Alan Miller (Hendersonville, TN).

Applicant: Mueller Industries, Inc. (Memphis, TN).

An incrementally positionable ball valve is described for use in the fluid circuit of a refrigeration or air conditioning system which can be remotely controlled by a low-amperage control signal.

The ball valve uses the pressurized refrigerant from the fluid circuit in which it is installed as the primary power medium to actuate the valve. A sensor provides feedback to a controller relating to the incremental position of the valve. It then controls the operation of the valve in accordance with predetermined parameters.

In another version, the ball valve incorporates locator detents so that its incremental position can be determined by an operator manually controlling the valve. In still another aspect, a restrictor is provided for varying the flow capacity of the valve.

U.S. Patent 6,216,481: Refrigeration system with heat reclaim and with floating condensing pressure.

Inventor:Jordan Kantchev (Longueuil, PQ, Canada).

Applicant: None.

In this invention, a heat pump system is installed on the discharge line of a refrigeration system with floating head pressure (condensing temperature as low as 60°F) to extract the total rejected heat from the refrigeration system. The heat pump system then elevates the temperature level of the total rejected heat to a value usable in heat reclaim coils, for the purpose of providing comfort heating of the building during cold periods of the year.

When no heat reclaim is required, the heat pump system is used for air conditioning and subcooling purposes.

U.S. Patent 6,209,574: Freon lock box.

Inventor: Todd J. Prewitt (The Woodlands, TX).

Applicant: None.

A lockable box is detailed which may be positioned around the gauge ports on the refrigerant lines of an air conditioning system, then closed and locked, thereby preventing unauthorized access to the ports and bleed off of refrigerant.

A problem has arisen with refrigerant systems in the form of unauthorized persons opening valves and/or fittings on the refrigerant lines in order to inhale the escaping refrigerant gas. Youths, in particular, have done this on occasion for the “high” they receive from sniffing the gas. Unfortunately, a number of persons, in particular teens, have died from the adverse effects of inhaling large quantities of refrigerant.A need exists, then, for a lock box such as this which prevents unauthorized access to valves and/or fittings of an air conditioning unit, says the inventor.

U.S. Patent 6,209,335: Environ-mental distribution control module.

Inventor: David Nowaczyk (Carol Stream, IL).

Applicant: David Nowaczyk (Carol Stream, IL).

Described here are enhanced controls added to conventional heating and air conditioning equipment that are designed to provide a uniform comfort environment throughout the structure.

The control module monitors variously placed sensors within the building and compares them to a settable difference limit. When excessive differences in temperature exist during cooling or heating mode, the control activates a blower fan which mixes the air until uniformity of sensed conditions is attained, thereby maintaining uniform comfort economically, says the inventor.

U.S. Patent 6,206,652: Compressor capacity modulation.

Inventor:Jean-Luc Caillat (Dayton, OH).

Applicant: Copeland Corp. (Sidney, OH).

A pulsed modulated capacity system for refrigeration, air conditioning, or other types of compressors is depicted in which suitable valving is provided which serves to cyclically block flow of suction gas to the compressor.

A control system is supplied which is adapted to control both the frequency of cycling as well as the relative duration of the on/off time periods of each cycle in accordance with sensed system operating conditions, to maximize the efficiency of the system. Preferably, the cycle time will be substantially less than the time constant of the load and will enable essentially continuously variable capacity modulation from zero to the full capacity of the compressor.

Additional controls may be incorporated to modify one or more of the motor operating parameters to improve the efficiency of the motor during periods of reduced load.

U.S. Patent 6,196,468: Air condi-tioning and heating environmental control sensing system.

Inventor: Dennis Guy Young (Kailua-Kona, HI).

Applicant: None.

A device for controlling an hvac system is described in which opening a door or window for more than a preset delay period causes the fan and compressor to be deactivated.

The door/window sensors preferably are wireless for ease of installation and maintenance. Optionally, an occupancy sensor and timer may be provided to turn off the system if the room is unoccupied beyond a delay period. Also as an option, a secondary thermostat may be provided so that if the room is unoccupied, the hvac system will operate at energy saving settings. People using hvac systems may leave doors or windows open for fresh air or other reasons, therefore causing the air conditioning or heating system to operate at a nearly continuous level. Contin-uous operation of the system causes high energy and maintenance costs because it prevents the environment from reaching the temperature setting of the thermostat. This problem is especially acute in hotels and resort vacation rental facilities.

This control system provides a method to prevent excessive and wasteful energy consumption and premature maintenance and replacement costs, says the inventor.