Combined Heating and Ventilation Unit with Zone Temperature Control
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Solution Overview
Problem
Existing ventilation systems face challenges in energy efficiency and climate control due to dependency on extract air temperature for heating supply air, leading to potential drafts and inefficiencies in heat recovery, while also requiring extensive construction and occupying space with large ducts and fan/heater arrangements.
Innovation Solution
A ventilation unit with a mixing zone for external and recirculated air, a heat exchanger for heat recovery, and an air temperature control arrangement that allows for different airflow temperatures to be distributed to various zones within the building, using a casing to house the inlets, mixing zone, and distribution outlets, along with a control system to manage airflow ratios and temperature variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If heat recovery ventilation is used to recover heat from extract air, then energy efficiency is improved, but the supply air temperature becomes dependent on extract air temperature leading to potential drafts and climate control difficulties
Solution Approach 1:
The ventilation system is divided into separate functional modules: a heat recovery unit that recovers heat from extract air, a mixing zone that combines fresh air with recirculated air, and a distribution system with individual zone control. This segmentation allows heat recovery to operate independently while zone temperature control is managed separately through the mixing arrangement and controllable outlets.
Solution Approach 2:
Recirculated air from the building acts as an intermediary medium between the heat recovery process and the final supply air. By mixing recovered fresh air with warm recirculated air, the system decouples the supply air temperature from direct dependence on extract air temperature, preventing drafts while maintaining energy efficiency.
2Temperature
If traditional fluid heating systems with radiators are used, then space heating is provided, but considerable construction effort, cost and space occupation are required
Solution Approach 1:
The ventilation system is designed to perform multiple functions: it provides fresh air ventilation, recovers heat from extract air, recirculates indoor air, and distributes heated air to various zones. By integrating heating functionality into the ventilation ductwork, the system eliminates the need for separate radiator installations, reducing construction complexity and space occupation.
Solution Approach 2:
The heating function is merged with the ventilation system. The ventilation ductwork serves dual purposes: transporting fresh air for ventilation and distributing heated air for space heating. The mixing zone combines heated fresh air with recirculated air, and this mixed air is then distributed through the ventilation outlets to provide zone heating.
3Temperature
If large ducts and fan/heater arrangements are used for air distribution, then heating capability is provided, but space is occupied and construction effort increases
Solution Approach 1:
The heating and distribution functions are nested within the existing ventilation ductwork structure. Rather than installing separate large ducts for heating, the system utilizes the ventilation ducts as the distribution network. The fan and heater components are integrated into the ventilation unit, with the heater positioned to heat air that then flows through the ventilation ducts to various zones.
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 solution enhances energy efficiency by recovering heat from extracted air and allows for precise temperature control of supply air, reducing construction needs and space occupation by integrating heating within the ventilation ductwork, enabling flexible and efficient climate control across different building zones.
Implementation Method 1
a heat exchanger to permit heat exchange between extracted air (air being extracted from internally of the building to be exhausted externally of the building) and the external ventilating air drawn into the unit from externally of the building
Implementation Method 2
heat recovery from the extracted air and improves the overall efficiency of the unit
Implementation Method 3
a mixing zone for mixing of the external air and the air drawn from the building
Implementation Method 4
an air temperature control arrangement providing airflows of different temperatures to be distributed via the distribution outlet arrangement to the different zones internally of the building
Data Source
Figure 1
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AI summary
A ventilation unit for a building has an inlet (26) for air drawn from the building and to be recirculated to the building, an inlet for external air (12) drawn from externally of the building; and a mixing zone (5) for mixing of the external air and the air drawn from the building. The unit also includes an air distribution outlet arrangement (30) for distribution of air to different zones internally of the building, and an air temperature control system providing airflows of different temperatures to be distributed via the distribution outlet arrangement to the different zones internally of the building.