Refrigeration heat pump and auxiliary heating apparatus control system with switchover during low outdoor temperature
US4598764A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 9, 1984 |
| Grant date | Jul 8, 1986 |
| Priority date | — |
| Expiry date | Oct 9, 2004 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF24F2221/34
- WIPO fieldThermal processes and apparatus
- WIPO sectorMechanical engineering
Abstract
A control system for a refrigeration heat pump apparatus and an auxiliary heating apparatus has a two stage thermostat with the first stage normally controlling the heat pump apparatus and the second stage normally controlling the auxiliary heating apparatus. An outdoor temperature thermostat is used to transfer the control of the auxiliary heating apparatus to the first stage when the outdoor temperature drops below a predetermined value and the heat pump is deenergized as its efficiency drops at that low outdoor temperature. Each of the stages of the thermostat has an anticipation means such as a heater to artificially heat the temperature responsive element. In order to improve the control and reduce the large change in temperature when the auxiliary heat is switched over to the first stage, both of the anticipation heaters of the first and second stage are connected to be controlled by the first stage during the operation of auxiliary heat by the first stage.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.