Heat Pump Apparatus Direct Evaporation District Heating
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Solution Overview
Problem
Existing heat pump systems are inefficient in cooling and heating, particularly in district heating networks, as they rely on closed cycles and external heat exchangers, which limit evaporation and condensation temperatures, leading to suboptimal performance and energy loss.
Innovation Solution
A thermally driven heat pump apparatus that utilizes direct evaporation and condensation of district heating water within the system, eliminating the need for external heat exchangers by depressurizing water inside the evaporation unit, allowing evaporation at lower temperatures and condensation at higher temperatures, thereby enhancing energy efficiency and performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If external heat exchangers are used in closed cycle heat pump systems, then heat transfer is enabled, but evaporation and condensation temperatures are limited resulting in suboptimal performance
Solution Approach 1:
The patent extracts the heat transfer function from external heat exchangers and performs evaporation and condensation directly within the district heating water loop. District heating water is depressurized inside the evaporation unit to enable direct evaporation, and condensed vapor is returned directly to the heating network, eliminating the need for external heat exchangers and the associated temperature limitations and thermal losses.
Solution Approach 2:
The patent merges the heat pump cycle with the district heating water loop by using the same water for both heating distribution and as the working fluid for evaporation and condensation. This integration allows the heat pump to operate at optimal temperatures while directly interacting with the heating network, improving overall system efficiency and reducing thermal losses.
2Productivity
If district heating water is depressurized inside the evaporation unit for direct evaporation, then evaporation temperature is reduced to 70°C improving efficiency, but system pressure control becomes more complex
Solution Approach 1:
The patent introduces a controller as an intermediary that automatically manages the pressure control valve based on detected pressure levels. The controller receives pressure signals from the evaporation unit and adjusts the pressure control valve accordingly, simplifying the overall system operation while enabling precise pressure control for optimal evaporation at 70°C.
3Loss of energy
If direct evaporation and condensation of district heating water is implemented, then thermal losses are reduced and energy efficiency increases, but the system requires precise pressure and temperature control
Solution Approach 1:
The patent implements feedback control mechanisms where sensors detect pressure and temperature levels in the evaporation unit and condenser, and the controller automatically adjusts the pressure control valve and system operation to maintain optimal conditions. This feedback loop simplifies operation by automating the precise control needed for direct evaporation and condensation, reducing thermal losses while maintaining ease of operation.
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 approach increases the efficiency of district heating systems by enabling evaporation at 70°C compared to 75°C, reduces thermal losses, and allows for optimal use during hot periods, improving the overall performance and energy transfer within the district energy network.
Implementation Method 1
an evaporator, such as an evaporation tank configured to evaporate by direct evaporation a liquid received from an external liquid source through a liquid inlet line and an evaporator inlet to an evaporation chamber, the pressure in the evaporation chamber being lower than the pressure in the liquid inlet line and sufficient low for evaporating the liquid entering the evaporation chamber
Implementation Method 2
allowing for generating a pressurized vapor leaving the evaporator through an evaporator vapor outlet
Implementation Method 3
an expander having an expander inlet and an expander outlet, the expander inlet having a fluid connection to the evaporator vapor outlet for receiving pressurized vapor from the evaporation to drive the expander
Implementation Method 4
a compressor having a compressor inlet and a compressor outlet, the compressor being operatively driven by the expander for compressing a gas from a low pressure, low temperature inlet gas at the compressor inlet to a high pressure, high temperature outlet gas at the compressor outlet
Implementation Method 5
a first condenser having a first condenser inlet and a first condenser outlet, the first condenser inlet having a fluid connection to the expander outlet and being configured for condensing the fluid received from the expander
Data Source
Figure 1
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AI summary
The present invention provides a heat pump apparatus comprising a Rankine cycle and an Carnot cycle part when implemented for cooling. The Rankine cycle comprises an evaporator (7) configured for evaporating by direct evaporation water received from an external water source (1). An expander (7) receives steam from the evaporator (21) and drives a compressor (9) compressing the fluid of the Carnot cycle. The fluid is thereafter condensed in a condenser (13b) and evaporated in an absorber (18).