Ventilation Heat Pump Layout for Exhaust-Air Heat Recovery
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Solution Overview
Problem
Existing heat pump systems for building heating face inefficiencies and high costs in achieving effective heat recovery and distribution, particularly in modern buildings like passive houses, where energy-saving measures are crucial.
Innovation Solution
The system incorporates a preheater, air/air heat exchanger, and air heater with a refrigerant circuit using CO2 in a supercritical state, allowing for needs-based preheating of outside air and efficient heating of supply air through a gas cooler and evaporator, while minimizing entropy increase and exergy loss, and includes a buffer storage tank with optimized geometry for efficient heat transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional water-based heat distribution system is used, then heat can be effectively distributed to rooms, but the system complexity and installation costs increase
Solution Approach 1:
The patent replaces the conventional water-based mechanical heat distribution system with an air-based heat pump system. The heat pump uses a refrigerant circuit to directly heat air, which is then distributed through the building's ventilation system, eliminating the need for separate radiators, pipes, and water circulation infrastructure.
2Loss of energy
If heat recovery from exhaust air is implemented, then energy efficiency improves, but the device complexity and cost increase
Solution Approach 1:
The patent merges the heat recovery function with the building's existing ventilation system. The heat pump integrates both heating and ventilation functions, using the same air handling units to recover heat from exhaust air and condition fresh air, thereby avoiding additional separate heat recovery equipment.
Solution Approach 2:
The heat pump system performs multiple functions simultaneously: it provides space heating, recovers heat from exhaust air, conditions fresh air for ventilation, and maintains indoor air quality. This multi-functionality eliminates the need for separate systems for each function.
3Power
If the refrigerant circuit heating output is increased to meet high temperature demands, then heating performance improves, but energy consumption and exergy loss increase
Solution Approach 1:
The patent employs variable speed drives on the compressor and fans to dynamically adjust operating parameters based on heating demand and outdoor temperature. The system operates at optimal part-load conditions rather than constant high output, reducing exergy losses while meeting varying heating requirements.
Solution Approach 2:
The heat pump system dynamically adapts its heating output to match the actual thermal demand of the building. The control system continuously adjusts refrigerant flow, air handling rates, and heat exchanger surface area utilization to maintain high efficiency across different operating conditions.
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 configuration enables efficient and cost-effective heating of buildings by optimizing the heating output of the refrigerant circuit, reducing energy losses, and providing a flexible heating solution that adapts to varying temperature demands, suitable for low temperatures and passive house standards.
Implementation Method 1
a preheater (270), which is suitable for a needs-based preheating of outside air (AU) to a minimum temperature value
Implementation Method 2
the air/air heat exchanger (200), which is suitable for heating the outside air (AU) by means of exhaust air (AB) using separate materials
Implementation Method 3
an air heater (230), with which the outside air can be tempered to an inlet air temperature (tGA)
Implementation Method 4
a refrigerant circuit using CO2 in a supercritical state, allowing for needs-based preheating of outside air and efficient heating of supply air through a gas cooler and evaporator
Implementation Method 5
includes a buffer storage tank with optimized geometry for efficient heat transfer
Data Source
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AI summary
The invention relates to a heat pump system (1) having a refrigerant circuit (100) for generating heat, a primary feed line (701), a gas cooler (170) for the refrigerant circuit (100) and a return line (730) in which a heat transfer medium can flow, and an air-to-air heat exchanger (200). A pre-heater (270) is mounted in a flow direction (x) of external air flowing into the heat pump installation (1), said pre-heater being suitable for pre-heating external air (AU) to a minimum temperature value (tM) as required. The air-to-air heat exchanger (200) is mounted in a flow direction downstream of the pre-heater (270) and is suitable for the physically separate heating of the external air by means of exhaust air. An air heater (230) as the heat transfer medium-to-air heating unit is mounted in a flow direction (x) downstream of the air-to-air heat exchanger (200) and is suitable for adjusting the temperature of the external air to a supply air temperature (tGA).