DE4436985A1 - Binary quantised power output controller for heating or air conditioning plant - Google Patents

Abstract

The heating or air conditioning plant uses compressors of the reciprocating piston, rotary piston or axial type, or absorption compressors. Several compressors are installed in the plant in blocks with unequal power output. For open-loop or closed-loop control, these compressors are coupled together according to power demand, from which a binary-decimal power quantisation results. The individual compressors are completely or partly controlled in a continuously variable fashion.

Description

State of the art

• a) It is known, the cooling / heating output adjustment of a heat pump (WP) for heating and air conditioning to implement with a two-point control (ON-OFF).
• b) It is also possible to determine the performance range of a heat pump for heating and air conditioning units a stepless (electrical) speed control over a certain frequency range by means of an elec tronic inverter control to regulate as required.
• c) For large leaps in performance, refrigeration technology uses composite systems consisting of at least two same compressors applied.

problem

The invention specified in claim 1 is based on the problem that very large necessary Performance spectrum of a heating period with a heat pump corresponds optimally in its working points according to the required power and the external climatic conditions according to the physical nature to be able to operate (Carnot Law).

• Re a) The two disadvantages result from the following disadvantages:
  The compressor (electric compressor) is designed for its maximum performance (e.g. at -14 ° C standard outside temperature) and would only need to be designed for 25% of this maximum performance to cover the average heating requirement. This means that it requires twice as much energy due to the high switching frequency (ON-OFF) and the non-optimized operation (optimal working point of the power machine). The compressor of a heat pump for heating and air conditioning units is designed for the temperature level Δt = 50 K, but in most cases would only need to raise the temperature level by Δt = 25 K. This ultimately leads to the fact that the labor figures are only half as large as in the optimal work area. This poor efficiency with monovalent air heat pumps is known to have led to the introduction of the bivalent mode of operation, which, however, leads to a much more expensive investment due to the additional boiler.
• to b) A continuously variable speed compressor (electronic inverter technology) is used in a larger one Speed range regulated according to the frequency range. Analogous deviations arise here from the optimal operating point of the compressor. Compressors have a certain optimal operating point, which is defined by a corresponding speed. For this speed or the optimal Ar At the point of operation, compressors are designed or constructed. With speed-controlled compressors, the Ener Energy savings due to the performance adjustment from the deviation from the optimal working point tet or partially compensated.

Due to the fluctuation range of the outside temperatures from -15 to + 15 ° C for the heating season one should Speed range from 5 to 140% can be realized. A Fre is currently technically possible and reasonable frequency control range from 30 to 90 Hz d. H. from 40 to 100% of the necessary power. With Invertertech  The entire performance spectrum of a heating period with monovalent air heat pumps can be done in this way regulate with only half.

solution

The problem of heating / cooling capacity adjustment is solved by the features listed in claim 1. The output adjustment of the heat pump - consisting of several compressors (compressors) of different output - is achieved by the binary [2 ⁿ ] -dual control of the compressors, which results in a binary-decimal output quantization.

Achieved advantages

The advantages achieved in the invention are in particular that with the invention Control technology the number of work (compared to WP with the currently known control methods) in Annual mean significantly increased and an optimized performance adjustment is achieved. The compressors who controlled in the "ON-OFF" switching mode and thus constantly operated at optimal speeds. The before parts of the digital binary-decimal performance adjustment in line with several unequal compressors with optimal compression working points, the continuous speed control of an individual is superior Heat pump compressor, which is used in comparison as the only alternative control method can be.

Favorable application options for such a binary heat pump control system result from Use of a rotary piston compressor, whereby direct condensing refrigerant is used, resulting in a Higher thermal efficiency results by eliminating a second heat cycle.

The use of inexpensive, environmentally friendly refrigerants such as propane, isobutane ect. leads to higher performance increase of the heat pump of about 15% compared to the currently most common ver used refrigerant R22 results. This is achieved through lower pressure ratios of the refrigerant Pro pan according to the Ig p, h diagram. A positive side effect from an economic point of view is that much longer service life of the heat pump system using propane due to the low Pressure ratios.

Claims (2)

1. heat pump systems for heating and air conditioning, consisting of compressors / compressors (e.g. motor compressors such as reciprocating, scroll, rolling pistons, screw compressors; or absorption compressors), characterized in that several compressors with unequal performance in the system, be installed in the block or in the system, with the compressors with unequal output being coupled to one another depending on the output requirement for output regulation or control, which results in a binary decimal compressor output quantization. 2. Heat pump systems according to claim 1, wherein the individual compressors in whole or in part can be steplessly regulated or controlled.