Multi-Unit Heat Pump Evaporation Control for Energy Efficiency
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Solution Overview
Problem
Conventional heat pump systems with multiple usage units connected to a single heat source unit often operate inefficiently as they maintain the minimum water temperature across all units, leading to unnecessary energy consumption and reduced efficiency.
Innovation Solution
A heat pump system with a variable-capacity compressor and flow rate adjustment valves, where the operating capacity of the compressor and circulation pumps are controlled to optimize the evaporation temperature of refrigerant in each usage unit, allowing for different set temperatures for each unit and preventing inefficient operation by adjusting flow rates and pump capacities based on temperature differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the system operates at the minimum water temperature predicted among all usage units, then all usage units can receive water at a temperature that meets their requirements, but the operating efficiency of the heat pump decreases unnecessarily
Solution Approach 1:
The system segments the temperature control for each usage unit independently. The control device calculates a separate target evaporation temperature for each usage unit based on its specific water temperature requirements, rather than using a single system-wide minimum temperature. This segmentation allows each usage unit to operate at its optimal temperature point.
Solution Approach 2:
The system dynamically adjusts the target evaporation temperature for each usage unit based on real-time temperature requirements. The control device continuously monitors the water temperature in each usage unit and adjusts the corresponding target evaporation temperature dynamically, allowing the system to adapt to changing conditions rather than operating at a fixed minimum temperature.
2Loss of energy
If different target evaporation temperatures are set for each usage unit, then operating efficiency is improved, but control complexity increases
Solution Approach 1:
Each usage unit essentially controls its own target evaporation temperature based on its specific temperature requirements. The control device automatically calculates and adjusts the target evaporation temperature for each usage unit independently, making the system self-regulating without requiring complex centralized coordination or additional manual control mechanisms.
3Reliability
If the compressor capacity is adjusted based on the minimum target evaporation temperature, then the system can meet the lowest temperature requirement, but other usage units may experience unnecessary temperature fluctuations
Solution Approach 1:
The control device segments the compressor capacity adjustment by calculating separate target evaporation temperatures for each usage unit. Instead of adjusting compressor capacity based on the minimum temperature alone, the system determines the appropriate compressor capacity for each usage unit independently, allowing for more stable and precise temperature control in each segment.
Solution Approach 2:
The system applies local quality control by adjusting the target evaporation temperature according to the specific temperature requirements of each usage unit. Each usage unit receives a target temperature optimized for its local conditions rather than a uniform system-wide temperature, improving both reliability and stability.
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 enables the system to supply an aqueous medium at optimal temperatures to each usage unit, preventing unnecessary inefficiency and allowing for the use of water at different temperatures without constant operation at the minimum predicted temperature, thus enhancing overall system efficiency.
Implementation Method 1
The compressor is a variable-capacity-type compressor for compressing refrigerant
Implementation Method 2
The heat source-side heat exchanger is capable of functioning as a radiator of refrigerant
Implementation Method 3
The usage-side heat exchangers function as evaporators of refrigerant and can cool an aqueous medium
Implementation Method 4
The usage-side heat exchangers function as evaporators of refrigerant
Data Source
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AI summary
It is an object of the invention to prevent unnecessary inefficiency in a system in which a plurality of usage units that use an aqueous medium are connected to a single heat source unit. A heat source unit (2) has a capacity-variable heat source-side compressor (21) and a heat source-side heat exchanger (24) which functions as a radiator of refrigerant. Each of usage units (4a, 4b) connected to the heat source unit (2) have usage-side heat exchangers (41a, 41b) which function as evaporators of refrigerant and cool an aqueous medium. An operating capacity controller (12b) controls the capacity of the heat source-side compressor (21) so that evaporation temperature (Te) of refrigerant of each of the usage-side heat exchangers (41 a, 41 b) reaches a first target evaporation temperature (Tte1). Second target evaporation temperature calculation units (191a, 191b) calculate second target evaporation temperatures (Tte2a, Tte2b) for each of the usage units (4a, 4b), which allow the outlet temperatures of the aqueous medium in the usage-side heat exchangers (41 a, 41b) to reach set temperatures (Tsa, Tsb), and a first target evaporation temperature decision unit (12a) decides minimum value of the second target evaporation temperatures (Tte2a, Tte2b) as the first target evaporation temperature (Tte1).