Method and device for controlling a hybrid heating and ventilation system
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Solution Overview
Problem
Existing hybrid heating and ventilation systems face inefficiencies in utilizing solar energy due to the limited temperature range of propylene glycol mixtures and high investment costs in direct electricity conversion, with existing technologies not maximizing the coefficient of performance for renewable energy sources.
Innovation Solution
The system utilizes propylene glycol's thermal content to transfer heat to ethylene glycol, directing it through preheating and main storage units and a heat accumulator, optimizing energy distribution and storage, and leveraging geothermal energy to enhance solar energy utilization, with a central control unit managing the flow to maximize efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If propylene glycol mixture is used in solar collectors to achieve high temperatures for heating, then the temperature requirement for energy storage unit is met, but the usable period for solar energy is limited and the system efficiency decreases
Solution Approach 1:
The system segments the thermal energy storage into two separate units: a preheating storage unit for lower temperature heat (from solar collectors and heat pump) and a main storage unit for higher temperature heat (from solar collectors). This segmentation allows each unit to operate at optimal temperatures, extending the usable period of solar energy by storing heat at different temperature levels throughout the day and night.
Solution Approach 2:
The system changes the temperature parameters by which solar thermal energy is stored and utilized. Instead of requiring a single high temperature (60°C) for all storage, the system stores heat at multiple temperature levels (lower temperature in preheating unit, higher temperature in main unit), allowing solar energy to be utilized over a broader temperature range and extending its usable period.
2Use of energy by moving object
If direct conversion of solar energy into electricity is implemented, then renewable energy utilization is achieved, but investment costs increase significantly
Solution Approach 1:
The system replaces the photovoltaic conversion mechanism (solar panels converting sunlight directly to electricity) with a thermal conversion mechanism (solar collectors heating fluid). This substitution uses proven, cost-effective solar thermal technology instead of expensive photovoltaic systems, achieving renewable energy utilization at lower investment costs while maintaining high efficiency through the heat pump and storage system.
3Reliability
If propylene glycol is used as collector fluid in solar collectors, then resistance to high temperature is achieved, but efficiency in cold ground conditions decreases
Solution Approach 1:
The system uses an intermediary heat exchanger between the solar collector circuit (using propylene glycol for high temperature resistance) and the ground heat accumulator circuit (using ethylene glycol for cold ground efficiency). This intermediary allows each fluid to operate in its optimal temperature range, with propylene glycol in the solar collectors and ethylene glycol in the ground accumulator, thus resolving the contradiction between high temperature resistance and cold ground efficiency.
4Temperature
If solar thermal energy is stored at high temperatures, then heating requirements are met, but damage to solar collectors and boiling of collector fluid occurs
Solution Approach 1:
The system segments the thermal storage into two temperature zones: a preheating storage unit for lower temperature heat and a main storage unit for higher temperature heat. By segmenting the storage, the system can store solar energy at high temperatures in the main unit without causing damage to collectors, as the high temperature storage is separated from the collector circuit through a heat exchanger.
Solution Approach 2:
The system uses a heat exchanger as an intermediary between the solar collector circuit and the thermal storage units. This intermediary allows thermal energy to be transferred to storage at high temperatures without exposing the solar collectors to conditions that would cause boiling or damage, thus protecting the collectors while achieving high temperature storage.
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 doubles to triples the efficiency of solar energy exploitation for building heating and hot tap water, reducing electric energy consumption and extending the usable period for solar energy, while maintaining high performance and preventing damage to solar collectors.
Implementation Method 1
the thermal content thereof is transferred by a heat exchanger of the central control unit into ethylene glycol
Implementation Method 2
ethylene glycol, which is in turn circulated through the preheating radiator in a duct for incoming air of the heating and ventilation apparatus thus heating the air introduced from the outside
Implementation Method 3
propylene glycol circulating in solar collectors has attained a temperature of +8 °C
Implementation Method 4
solar energy is utilized in four different ways: once propylene glycol circulating in solar collectors
Implementation Method 5
heat is directed during cold winter season to heat the incoming air by circulating propylene glycol through the heat accumulator
Implementation Method 6
a heat exchanger cell operating using the countercurrent principle
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The invention relates to a method and apparatus for controlling a hybrid heating and ventilation system of a building, the system comprising a heating and ventilation apparatus (2), solar collectors (3), main energy storage and preheating storage units (14, 15), a heat accumulator (4) and a central control unit (1) for the system. The invention is characterized in that solar energy is utilized in four different ways, i.e. once propylene glycol circulating in the solar collectors (3) has attained the temperature of +8 °C, the thermal energy thereof is used to heat air feed introduced into the heating and ventilation apparatus (2), once propylene glycol is at about +30 °C, the thermal energy thereof is utilized to heat the preheating storage unit (15), once propylene glycol is at a temperature of more than +60 °C, the thermal energy thereof is utilized to heat the main storage unit (14), and once each storage unit (14, 15) has attained the temperature of +80 °C, thermal energy of propylene glycol is passed to a heat accumulator (4) arranged under the building to be utilized for heating incoming air during winter season.