Geo-Exchange Network Control for Peak Heating Without Oversized GHX
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Solution Overview
Problem
District geo-exchange systems face high capital and operating costs due to the large size of ground heat exchangers required for peak heating demands, which can lead to inefficient performance over time and increased economic costs, especially in urban areas where electricity is expensive and GSHP performance varies throughout the heating or cooling season.
Innovation Solution
A district geo-exchange system that includes sensors to measure real-time data from components like ground source heat pumps, heat sources, and heat sinks, along with a controller that generates predictive models for energy demand and supply forecasts using historical and weather data, allowing for optimization of energy distribution and potential use of alternative heat sources like groundwater or waste heat, thereby reducing the need for large ground heat exchangers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the size of the ground heat exchanger is increased to meet peak heating demand, then the heating capacity is improved, but the capital cost and drilling expense increase significantly
Solution Approach 1:
The system performs preliminary action by storing excess heat in the ground during periods when heating demand is low (such as daytime or off-peak hours). This pre-stored heat is then retrieved during peak demand periods, eliminating the need to size the ground heat exchanger for peak conditions. The controller manages this by activating the ground heat exchanger to store heat when demand is low and switching to the stored heat source when demand peaks.
Solution Approach 2:
The invention introduces an intermediary thermal storage mechanism between the ground heat exchanger and the heat pump system. This intermediary stores thermal energy temporarily, allowing the ground heat exchanger to operate at lower, more economical capacity while still meeting peak demands through the stored heat. The controller acts as the intermediary managing the flow and timing of heat transfer between these components.
2Reliability
If the ground heat exchanger is sized for peak demand, then heating reliability is improved, but the coefficient of performance deteriorates over the heating season
Solution Approach 1:
The controller implements feedback by continuously monitoring the temperature of stored heat and the current heating demand, then dynamically adjusting the operation of the ground heat exchanger and heat pump. This feedback loop ensures the system maintains optimal coefficient of performance by retrieving heat at appropriate temperature differentials and switching sources based on real-time conditions, preventing performance degradation over the heating season.
Solution Approach 2:
The system transitions from a static, fixed-capacity ground heat exchanger design to a dynamic system where the controller continuously adjusts heat transfer rates, source selection, and storage utilization based on varying demand conditions. This dynamic operation maintains optimal temperature differentials and heat pump efficiency throughout the heating season, preventing the performance deterioration that occurs with static oversized systems.
3Quantity of substance
If a large ground heat exchanger is installed to meet peak demand, then the heating coverage is improved, but the operating cost increases due to inefficient performance
Solution Approach 1:
The system applies self-service by using excess heat generated during low-demand periods to pre-charge the thermal storage, thereby serving its own peak demand requirements without additional external input. This self-sustaining approach allows the system to meet peak heating coverage while avoiding the inefficiency losses associated with oversized ground heat exchangers operating at partial load, thus reducing operating costs.
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 optimizes the operation of geo-exchange systems by reducing capital costs, improving energy efficiency, and maintaining consistent performance throughout the season by utilizing alternative heat sources, thus lowering operating costs and extending the economic return of the system.
Implementation Method 1
the GSHP transfers energy from a refrigerant to a working fluid within a conduit of the district pipe loop to a heat distribution mechanism within the plurality of buildings
Implementation Method 2
the GHX is comprised of pipes with a working fluid, the pipes buried in the ground in vertical or horizontal boreholes
Implementation Method 3
the GHX is comprised of pipes with a working fluid, the pipes buried in the ground in vertical or horizontal boreholes
Data Source
AI summary
A method and system for optimizing the operation of a geo-exchange system, by generating predictive models pertaining to energy demand and energy capacity for a particular building or district, based on data from sensors associated with components of a district geo-exchange system, historical and real-time operational data associated with district modules, including weather forecast data and current weather conditions.