Buffer Storage Heat Supply Layout for Low Return Temperature
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Solution Overview
Problem
Existing heat supply devices for buildings face challenges in maintaining a low return temperature, leading to inefficiencies and increased heat losses, particularly when there is low heat demand, and often fail to provide effective heating of rooms.
Innovation Solution
A device with a primary circuit containing a buffer storage and two heat exchangers, where the heat transfer medium flows through both heat exchangers on the primary side, and they are connected to separate consumption circuits, allowing for adjustable volume flows and temperature stratification in the buffer storage to manage heat distribution efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the return temperature is increased to reduce heat demand, then the heat consumption decreases, but the heat losses from the heat transport increase and the efficiency of the heat source decreases
Solution Approach 1:
The primary circuit is segmented into multiple parallel circuits (first primary circuit and second primary circuit) that can operate independently. This allows selective activation of circuits based on heat demand, enabling the system to maintain lower return temperatures by distributing heat through multiple pathways rather than relying on a single high-temperature return line.
Solution Approach 2:
A buffer storage unit is introduced as an intermediary between the heat source and the consumption circuits. The buffer storage accumulates heat during periods of low demand and releases it during high demand, decoupling the return temperature from immediate heat consumption requirements and enabling more efficient heat transport.
2Use of energy by moving object
If the return temperature is increased, then the heat demand is reduced, but the efficiency of the combined heat and power plant decreases
Solution Approach 1:
The system dynamically adjusts the operation of multiple primary circuits and the buffer storage based on real-time heat demand. During low-demand periods, the buffer storage absorbs heat at lower temperatures, while during high-demand periods, it releases stored heat, allowing the CHP plant to operate at optimal efficiency points regardless of instantaneous heat requirements.
Solution Approach 2:
The system changes operational parameters by switching between different circuit configurations and utilizing the buffer storage to modify the temperature and flow rate parameters. This allows the CHP plant to maintain its efficiency by decoupling its operation from the variable heat demand through parameter adjustment via the buffer storage and parallel circuits.
3Device complexity
If a single heat exchanger is used, then the device complexity is reduced, but the ability to provide both heating and hot water supply efficiently is compromised
Solution Approach 1:
The heat exchange function is segmented into multiple specialized heat exchangers (first heat exchanger for heating, second heat exchanger for hot water supply) arranged in parallel. Each heat exchanger is optimized for its specific function, allowing the system to efficiently serve multiple purposes while maintaining manageable complexity through functional separation.
Solution Approach 2:
The buffer storage unit serves multiple functions: it acts as a heat accumulator, a flow regulator, and a temperature stabilizer for both the heating circuit and the hot water supply circuit. This multi-functionality allows a single component to support multiple system functions, compensating for the increased number of heat exchangers.
4Productivity
If the volume flow through the heat exchanger is increased to meet high heat demand, then the heat supply capacity increases, but the return temperature increases leading to higher heat losses
Solution Approach 1:
The volume flow is segmented across multiple parallel primary circuits. Each circuit handles a portion of the total heat demand, allowing the system to increase overall heat supply capacity without proportionally increasing the return temperature in any single circuit. The buffer storage further segments the thermal load by storing excess heat during low-demand periods.
Solution Approach 2:
The buffer storage ensures continuous useful action by accumulating heat during periods when heat supply capacity exceeds demand and releasing it when demand exceeds supply. This continuous accumulation and release cycle allows the system to maintain high heat supply capacity while minimizing return temperature and associated heat losses through temporal load balancing.
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 design achieves a low return temperature, reduces heat losses, and allows for effective heating of both drinking water and rooms by optimizing heat distribution and consumption based on demand, enhancing the overall efficiency of the heat supply system.
Implementation Method 1
remove heat provided by a heat source placed at any location from the heat source by means of a heat transfer medium circulating through flow and return
Implementation Method 2
heat is removed from the heat transfer medium at the heat sink by means of a heat exchanger through which the heat transfer medium flows
Implementation Method 3
at least one buffer storage (06) filled with the heat transfer medium and through which flows is arranged in the primary circuit for the temporary storage of heat absorbed by the primary circuit from the heat source
Implementation Method 4
the heat given off by the heat transfer medium on the primary side is transferred through heat transfer and heat conduction
Implementation Method 5
A first heat exchanger (07) and a second heat exchanger (08) are also arranged in the primary circuit. The heat transfer medium flows through the first heat exchanger (07) and the second heat exchanger (08) on the primary side
Implementation Method 6
a pump (16) and, alternatively or additionally, a controllable valve (17) can be assigned to the flow (03) and/or return (04), whereby a volume flow flowing through the flow (03) and the return (04) can be adjusted and thus predetermined
Data Source
Figure 1
Figure 2
AI summary
A device (01) for supplying heat to buildings is described, comprising a primary circuit (02) through which a heat transfer medium flows and which is connected to a heat source (05) via a supply line (03) and a return line (04). At least one buffer storage tank (06), as well as a first heat exchanger (07) and a second heat exchanger (08), are arranged in the primary circuit (02). The heat transfer medium flows through the primary side of the heat exchangers (07, 08). The first heat exchanger (07) is connected on its secondary side to a first consumption circuit (09), and the second heat exchanger (08) is connected on its secondary side to a second consumption circuit (10). The second heat exchanger (08) is arranged in parallel to the buffer storage tank (06). A supply and outlet (14) connected to a cold area of the buffer storage tank (06), an outlet (15) of the second heat exchanger (08) and the return (04) merge into each other.A hot volume flow coming from the supply line (03) flows to a hot section of the buffer storage tank (06). Volume flows passing through the first heat exchanger (07) and/or second heat exchanger (08) on the primary side are drawn from the hot section of the buffer storage tank (06).