Multi-Stage Heat Pump Water Preheating From Surplus Heat
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Solution Overview
Problem
Existing heating installations are inefficient in utilizing heat energy for tap hot-water heating, as surplus heat from heat pumps is often wasted, and the heating process lacks effective preheating steps to optimize energy use.
Innovation Solution
A heating installation configuration with a first heat pump, a first heat exchanger as a subcooler, a second heat pump, a second heat exchanger for initial preheating, and a third heat exchanger for further preheating in series, along with an accumulator tank to store heat energy for peak demand, ensuring efficient heat utilization and preheating of tap hot-water in multiple steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If surplus heat from the first heat pump is directly discarded, then the system complexity is reduced, but energy efficiency deteriorates due to waste of heat energy
Solution Approach 1:
The patent converts the harmful waste heat from the first heat pump into a beneficial resource by routing it through a first heat exchanger to preheat water in the second circuit. This transforms previously discarded thermal energy into useful preheating capacity, reducing overall energy consumption while integrating seamlessly into the existing heat pump system.
Solution Approach 2:
The heating system is segmented into multiple functional stages: the first heat exchanger for initial preheating using surplus heat, the second heat exchanger for further preheating, and the second heat pump for final heating. This segmentation allows each component to operate optimally at different temperature levels, improving overall system efficiency without creating excessive complexity.
2Loss of energy
If a single heat exchanger is used for water heating, then the device complexity is reduced, but energy efficiency deteriorates due to inability to utilize heat energy at different temperature levels
Solution Approach 1:
Different heat exchangers are positioned at different locations in the thermal circuit to handle different temperature levels. The first heat exchanger operates with the warmer surplus heat from the first heat pump condenser, while the second heat exchanger handles the cooler heat from the second heat pump. This local optimization ensures each heat exchanger operates at its most efficient temperature range.
Solution Approach 2:
The second circuit serves multiple functions: it receives preheated water from the first heat exchanger, receives additional heating from the second heat pump, and delivers final hot water through the second heat exchanger. This multi-functional design allows a single circuit to handle multiple thermal tasks, reducing the need for separate dedicated systems.
3Reliability
If the first heat pump operates alone for all heating needs, then the system complexity is reduced, but reliability deteriorates when the heat pump is temporarily out of operation
Solution Approach 1:
The system changes operational parameters by switching between different heat sources based on availability. When the first heat pump is operational, it provides primary heating with surplus heat preheating. When the first heat pump is unavailable, the second heat pump can independently provide heating using the second heat exchanger. This parameter switching ensures continuous heating supply while maintaining reasonable system complexity.
4Loss of energy
If tap hot-water is heated directly to final temperature, then the heating process is simplified, but energy efficiency deteriorates due to lack of preheating steps
Solution Approach 1:
The system performs preliminary heating actions before the main heating process. The first heat exchanger preheats water using surplus heat from the first heat pump, and the second heat exchanger provides further preheating using heat from the second heat pump. This preliminary action reduces the energy burden on the main heating process, improving overall efficiency while adding structured heating steps.
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 allows for efficient utilization of low-grade and high-grade heat energy, achieving efficient preheating of tap hot-water and cooling of the medium, thereby increasing the efficiency of the first heat pump and enabling heating even when the first heat pump is temporarily out of operation.
Implementation Method 1
a first heat exchanger which is arranged in the second circuit and which is connected between a condenser and an expansion valve of the first heat pump in order to transfer heat from a working medium of the first heat pump to the medium in the second circuit
Implementation Method 2
a second heat pump arranged for heating a medium by absorbing heat energy from the medium in the second circuit
Implementation Method 3
a second heat exchanger which is arranged in the second circuit in order to transfer heat from the medium in the second circuit to water in a water supply line that is intended to be heated in order to provide tap hot-water
Implementation Method 4
a third heat exchanger which is arranged in the second circuit in order to transfer heat from the medium in the second circuit to the water in said water supply line
Data Source
AI summary
A heating installation comprising: --a first circuit (C1); --a second circuit (C2); --a first heat pump (4) for heating the medium in the first circuit; --a first heat exchanger (10) arranged in the second circuit (C2) and connected between a condenser (4b) and an expansion valve (4d) of the first heat pump; --a second heat pump (11) arranged for heating a medium by absorbing heat energy from the medium in the second circuit; and --a second heat exchanger (12) and a third heat exchanger (14) for transferring heat from the medium in the second circuit to water in a water supply line (13). The second heat exchanger (12) is connected to the water supply line upstream of the third heat exchanger (14) in order to allow the second heat exchanger to preheat the tap hot-water in a first step and the third heat exchanger to preheat the tap hot-water in a subsequent second step.