Geothermal heat pump device
Solution Overview
Problem
Existing geothermal heat pump systems require complex controllers and extensive programming to manage environmental conditions and underground heat exchangers, leading to potential freezing and breakdown issues during excessive heating operations.
Innovation Solution
A geothermal heat pump device that sets limit values for heat collection using detection data and device specifications, controlling the compressor operation frequency and expansion valve opening to prevent excessive heat usage and maintain efficient operation throughout the year.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If the ground stores heat during summertime and the stored heat is used during wintertime, then the geothermal heat pump system can operate all year round, but the amount of stored heat is limited and excessive heating operation consumes the stored heat before winter ends, causing the underground heat exchanger to freeze and break
Solution Approach 1:
The controller performs preliminary calculation of the heat collection limit value before excessive heat collection occurs. By calculating the limit value based on outlet temperature measurements and ground thermal characteristics, the system proactively prevents the underground heat exchanger from freezing and breaking, ensuring reliable year-round operation.
Solution Approach 2:
The system continuously monitors the outlet temperature of the heat medium water and uses this feedback to calculate the soil temperature and adjust the heat collection limit value. This closed-loop control ensures that the system operates within safe temperature thresholds, preventing freezing and breakdown of the underground heat exchanger while maximizing operational duration.
2Reliability
If the outlet temperature of heat medium water is measured using a temperature sensor and the soil temperature is calculated to set limit values, then the heat collection and release operations can be controlled, but a great many programs and data are required, resulting in complicated controllers
Solution Approach 1:
The invention extracts only the essential parameters needed for control - specifically the outlet temperature of the heat medium water - and calculates the soil temperature and heat collection limit value from this single measurement. This approach eliminates the need for multiple temperature sensors and complex environmental data input, significantly simplifying the controller while maintaining reliable control accuracy.
Solution Approach 2:
The controller uses the measured outlet temperature to automatically calculate both the soil temperature and the heat collection limit value without requiring external input data or complex programming. The system serves itself by deriving all necessary control parameters from a single temperature measurement, reducing controller complexity while ensuring accurate heat management.
3Reliability
If the heat pump stops operating or operates less actively to not exceed the set limit values, then the underground heat exchanger is protected from freezing, but the heating operation may be insufficient and user comfort is compromised
Solution Approach 1:
The heat collection limit value is dynamically adjusted based on the calculated soil temperature and ground thermal characteristics. Rather than using a fixed limit, the system adapts the operational threshold to current ground conditions, allowing maximum heating capacity while staying within safe temperature limits. This dynamic approach protects the underground heat exchanger while optimizing heating productivity.
Solution Approach 2:
The system changes the operational parameter (heat collection limit value) based on the calculated soil temperature. As the soil temperature changes throughout the winter season, the limit value is adjusted accordingly, allowing the heat pump to operate at higher capacity when ground temperatures are favorable and reducing capacity when temperatures approach critical thresholds, thus balancing protection and productivity.
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 allows for simple and effective management of heat collection, preventing underground heat exchanger freezing and breakdown, ensuring pleasant air conditioning and hot water supply while optimizing energy use and extending the system's operational period.
Implementation Method 1
causes brine as a heat medium to circulate through an underground heat exchanger, collects heat using the heat pump
Implementation Method 2
uses the ground as a heat source, causes brine as a heat medium to circulate through an underground heat exchanger
Implementation Method 3
a heat pump, and a water tank... the compressor increases a temperature and a pressure of the refrigerant
Implementation Method 4
the refrigerant flows into an evaporator, the refrigerant boils and evaporates
Implementation Method 5
the expansion valve performs expansion of the refrigerant, the refrigerant flows into an evaporator
Data Source
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AI summary
A geothermal heat pump device includes a heat pump heat source unit having a refrigerant circuit in which a compressor, a water-refrigerant heat exchanger, an expansion valve, and a refrigerant-brine heat exchanger in which a heat medium from an underground heat exchanger buried underground is connected such that the heat medium circulates are serially connected, a warm-water heater unit configured to supply warm water heated at the water-refrigerant heat exchanger to heating and air conditioning and hot water supply such that the warm water circulates, and a controller configured to control an upper limit of an operation frequency of the compressor based on a heat collection limit value set by comparing a unit necessary evaporation capacity calculated from information on the underground heat exchanger with a unit actual evaporation capacity calculated from inlet and outlet temperatures and a circulation flow rate of the heat medium circulating through the refrigerant-brine heat exchanger.