System and method for oil return in an HVAC system
US8327658B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 17, 2008 |
| Grant date | Dec 11, 2012 |
| Priority date | — |
| Expiry date | Aug 18, 2030 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02B30/70
- WIPO fieldThermal processes and apparatus
- WIPO sectorMechanical engineering
Abstract
A system and a method are provided for returning oil in a heating, ventilation, and air conditioning (HVAC) system by determining when an ambient zone temperature is equal to or less than a temperature limit and reversing a direction of refrigerant flow of the HVAC system based on the length of time. Also, a system and a method are provided for monitoring the length of operation in a first and a second heating mode and for reversing a direction of refrigerant flow based on the length of time operation occurs in the first and second heating modes. A system and a method having a first compressor, a first heating mode, a second heating mode, a defrost mode, and a controller is disclosed. The controller selectively controls initiation of the defrost mode in response to an HVAC system operating in a heating mode of operation for a predetermined amount of time.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.