Hybrid heating system using primary heating
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Solution Overview
Problem
Existing systems face challenges in efficiently producing cooling without an actual heat sink, particularly in buildings with district heating during summertime when there is no heat consumption, as the integration of heat recovery units with cooling functions is not practical.
Innovation Solution
A hybrid system comprising 2-6 heat pumps connected thermodynamically in series, with exhaust-air heat recovery devices and a fan configuration that allows for efficient cooling by directing heat between a chilled service water heat exchanger and a heating circulation heat exchanger, using district heating or alternative primary heat generators like electric boilers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If heat pumps are connected in series to produce cooling without a traditional heat sink, then cooling capability is improved, but system complexity increases
Solution Approach 1:
The heat pump system is designed to perform multiple functions: heating during winter and cooling during summer. The same heat pumps that provide heating when connected to district heating also provide cooling by reversing operation and using the district heating network as a heat sink, eliminating the need for separate cooling equipment.
Solution Approach 2:
The heat pumps are arranged in a series configuration where the condenser of one heat pump feeds into the evaporator of the next, creating a nested thermodynamic system. This allows efficient heat transfer between the heat pumps while maintaining compact system architecture.
2Reliability
If district heating is used for primary heating, then heating reliability is improved, but cooling production capability deteriorates
Solution Approach 1:
The system dynamically switches between heating and cooling modes based on seasonal demands. During summer, the heat pumps reverse operation to provide cooling, using the district heating network as a heat sink. During winter, they provide heating. This dynamic operation allows the system to adapt to different thermal demands throughout the year.
Solution Approach 2:
The system changes its operational parameters seasonally - in summer, heat pumps operate in cooling mode with reversed heat flow direction, using district heating water as a heat sink. In winter, they switch to heating mode. This parameter change allows the same infrastructure to serve dual purposes.
3Use of energy by moving object
If exhaust air heat recovery units are integrated with cooling functions, then energy efficiency is improved, but ease of operation deteriorates
Solution Approach 1:
The exhaust air heat recovery units are merged with the heat pump system, allowing the exhaust air to serve as an additional heat source for the heat pumps. This integration enables the system to recover energy from exhaust air while maintaining simplified operation through centralized control.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration achieves exceptional efficiency by maintaining a temperature difference of 40-95% across the system, enabling effective cooling even without a traditional heat sink, with flexible temperature adjustments and easy maintenance of components.
Implementation Method 1
2 - 6 heat pumps, most advantageously 3 - 5 heat pumps, connected in series
Implementation Method 2
service water heat exchanger 10, i.e. an upper service water heat exchanger and a heating circulation heat exchanger 14
Implementation Method 3
The fan of the exhaust-air heat recovery unit is before, in the direction of flow, the exhaust-air heat recovery elements
Data Source
Figure 1
AI summary
The object of the invention is a hybrid heating system, which includes • a primary circuit of a primary heat generator comprising in parallel at least one service water heat exchanger (10) and one heating-circuit heat exchanger (14) to be heated with the primary heat • a heating circuit (22) on the secondary side of the heat exchanger (14), • heat-pump units (HP1, HP2, HP3) connected in cascade, each comprising a compressor (31), an expansion valve (32), an evaporator (34) and a condenser (36a, 36b) and connected so as to utilize in series the exhaust-air heat recovery (20) by means of their evaporators (34) and so as to emit a secondary heat in series by means of their condensers (36a) as a unit in parallel with said primary heat heat exchanger (14), • the exhaust-air heat recovery unit (20) comprising a plurality of exhaust-air heat recovery elements (201, 202, 203) connected in series, wherein the medium circulations on both sides are connected in series and together are connected to a counter-flow so that a recurring rise in temperature of the medium and a recurring cooling of the exhaust air are realized.