ACHRNEWS

Innovations: A round-up of recent hvacr patents

April 20, 2000

U.S. Patent 5,979,169

U.S. Patent 5,979,169: Console air conditioning unit, including plenum. Inventor: Miller Price, Morristown, TN. Applicant: None. Issue date: Nov. 9, 1999.

The purpose of this invention is to facilitate the replacement of console package air conditioning units and provide a relatively low-cost replacement system. Another objective is to provide a more efficient unit.

The unit’s indoor cabinet is subdivided into a plenum compartment having an air discharge opening and either a machinery compartment or a room air return compartment. The machinery compartment may contain either a water-source heat pump or a simple fancoil unit.

Alternatively, an outdoor package unit may be connected so as to draw in return air via the room air return compartment and discharge conditioned air via the plenum compartment.

One advantage, according to the inventor, is cost. To replace a console package unit with a unit of the same type typically costs about $8,000. This system, which employs stock standard air conditioning or heat pump components, can be provided at a cost of approximately $4,000.

Also, current standard air conditioning components have much higher efficiencies compared to the components used in the older console package units being replaced (and compared to the nearly identical replacement units conventionally installed).

The use of current components allows an improvement in efficiency of 40% to 45% compared to conventional console package units, says the inventor. Also, the unit is quieter, particularly when the compressor is located outside.

In addition to retrofit applications, the invention is said to be suitable for new installations.

U.S. Patent 6,015,270

U.S. Patent 6,015,270: Linear compressor or pump with integral motor. Inventor: Bruce A. Roth, Chandler, AZ. Applicant: Air Conditioning Technologies, Mesa, AZ. Issue date: Jan. 18, 2000.

While linear motor-based compressors and pumps offer theoretical advantages, such as mechanical simplicity and reduced friction, compared to traditional reciprocating machines, there are design challenges which must be addressed in order to make them a practical alternative.

The intent of this invention is to provide a compressor capable of operating efficiently over a wide range of varying pressure and flow conditions. It is also an objective to provide a reciprocating compressor or pump whose stroke length and speed can be varied independently while in operation.

The unit is also designed to have few moving parts and to be capable of operating with a minimum of lubrication.

This invention is based on a multiphase, electronically controlled tubular electric motor with a cup-shaped stator. In this design the stator is the moving part, in the shape of a hollow cylinder closed at one end and having a one-way valve in the closed end of the cylinder, referred to as the interstage valve.

The stator acts as a moving piston on its outer diameter and a moving cylinder on its inner diameter. A hollow cylinder or discharge tube acts as a fixed piston working in this moving cylinder. A discharge valve may be fitted at the end of this central cylinder for compressor applications.

As the stator reciprocates, the working fluid is drawn in through the intake valve, compressed and transferred through the interstage valve, and forced out through the central cylinder.

U.S. Patent 6,018,957

U.S. Patent 6,018,957: Method and apparatus for controlling beats and minimizing pulsation effects in multiple compressor installations. Inventors: Thomas S. Katra, Fayetteville, NY, and Richard J. Wood, North Syracuse, NY. Applicant: Carrier Corp., Syracuse, NY. Issue date: Feb. 1, 2000.

When an air conditioning or refrigeration system has varying load requirements, it is common to use a bank of compressors. The compressors may have different capacities and can be run individually or in various combinations to provide more efficient operation for the varying loads.

In positive-displacement compressor systems, gas pulsations, vibrations, and sound radiation occur at exact multiples of compressor running speed. When two (or more) similar positive-displacement compressors are operated in the same refrigerant circuit, or in separate circuits in the same equipment room, only a slight difference in running speed causes beats to occur due to the slight differences in the frequencies.

These beats are both annoying and potentially damaging. Because compressors most commonly use induction motors as drives, these slight differences will occur.

With this invention, one compressor has its speed controlled to exactly match the speed of the other compressor so as to eliminate beats. A feedback control system and a variable-frequency drive (vfd) are used to match the speeds and minimize the amplitude of at least one of the gas pulsation harmonics by additionally controlling the phasing of the vfd-driven compressor.

The invention also minimizes the pressure pulsation effect in multiple-compressor installations.

U.S.Patent 6,021,953

U.S. Patent 6,021,953: Year-round air conditioning apparatus and method. Inventor: Ross M. Swan, Stirling, Canada. Applicant: None. Issue date: Feb. 8, 2000.

The purpose of this invention is to provide exchange of air in the enclosed space of a building year-round while providing dehumidification when the space is being cooled.

In order to provide this, a fan is mounted on or otherwise provided adjacent to the bottom floor, such as the basement floor of a building, to remove air from the bottom floor level. The air is discharged through a conduit to an outlet which is connected to an opening in an outside wall.

Vents may be provided in upper floors for routing relatively drier upper air toward the bottom floor to replace relatively more humid air being removed. A fresh-air intake valve may be provided in an opening in an outside wall, preferably near the top of the enclosed space, to replace the relatively humid air being discharged.

U.S. Patent 6,023,667

U.S. Patent 6,023,667: Oil burner motor and refrigeration and air conditioning motor diagnostic apparatus. Inventor: Edward Johnson, Clifton Park, NY. Applicant: None. Issue date: Feb. 8, 2000.

According to the inventor, there is a need to monitor the operation of an oil burner and keep track of the fuel consumed and the fuel remaining in the supply tank. In addition, there is a need to monitor the cycle time of refrigeration compressors for operating efficiency.

The invention provides a device that senses the presence of an electrical field induced around an electrical motor or off a burner ignition coil, without requiring an electrical or mechanical connection to an oil burner or refrigeration unit.

The apparatus provides a device to record:

  • The cumulative time the burner runs during a given period;
  • Any occurrence of a run time that is shorter than or equal to “lock out” or failure mode;
  • The time elapsed between the beginning of the current run and the end of the previous run;
  • The date and time to initiate a telephone call for reporting data;
  • The ability to send this data to a remote monitoring and diagnostic device for analysis; and
  • The ability to receive updated instructions from the remote device.

The invention also provides a means to determine fuel consumption of an oil burner, as well as burner efficiency, by comparing actual fuel consumption with theoretical consumption.

Another objective of the invention is to provide an apparatus to track and record the duty cycles of refrigeration compressor motors to ensure that they are running within acceptable limits.