Condensate Spray Heat Recovery for Fresh-Air HVAC Loads
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Solution Overview
Problem
Existing HVAC systems face inefficiencies in managing thermal loads due to the high enthalpy content of fresh air, leading to significant energy consumption in heating and cooling processes, with conventional methods discarding condensate energy that could be utilized for improved efficiency.
Innovation Solution
The system incorporates a condensate energy recovery method by using a pump to spray collected condensate into the air path within the HVAC system, enhancing heat transfer efficiency through heat exchangers and chiller components, with optional additional stages and condenser precooling to maximize energy savings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fresh air is brought into the building to provide appropriate air quality, then air quality is improved, but thermal load increases due to high enthalpy content
Solution Approach 1:
The system performs preliminary cooling of fresh air using a heat exchanger before it enters the occupied space. The heat exchanger pre-cools the high-enthalpy fresh air using cooler return air or condensate water, reducing the thermal load on the HVAC system before the air requires conditioning.
Solution Approach 2:
The patent introduces an intermediary heat exchanger and condensate spray system between the fresh air intake and the occupied space. This intermediary component transfers thermal energy from the hot fresh air to cooler media (return air or condensate), reducing the enthalpy of fresh air before it enters the building.
2Use of energy by moving object
If condensate is collected and sprayed into the air path, then heat transfer efficiency is improved, but system complexity increases
Solution Approach 1:
The system uses the condensate that is already produced by the cooling coil to cool the fresh air or chiller condenser. This self-service approach recycles waste condensate for useful cooling purposes, improving heat transfer efficiency without requiring external cooling resources.
Solution Approach 2:
Instead of discarding the condensate collected from the cooling coil, the system recovers its thermal energy by spraying it into the air path or onto the chiller condenser. This recovery process extracts useful cooling capacity from what would otherwise be wasted condensate.
3Loss of energy
If an enthalpy wheel is used to exchange energy between fresh air and extracted air, then energy saving efficiency is improved, but cost increases
Solution Approach 1:
The patent replaces the expensive enthalpy wheel with a simpler, more economical solution using standard heat exchanger components and spray systems. While the enthalpy wheel provides continuous energy recovery, the spray system achieves comparable energy savings at lower cost using readily available components.
Solution Approach 2:
The system extracts the essential function of energy recovery from the complex enthalpy wheel mechanism and implements it through a simpler heat exchanger and spray system combination. This extraction approach separates the cooling function from the moisture transfer function, achieving energy savings without the complexity and cost of a full enthalpy wheel.
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 results in energy savings of up to 28% compared to traditional systems by optimizing heat transfer and humidity management, reducing the overall energy consumption of the air conditioning system.
Implementation Method 1
a heat exchanger for providing heat transfer between air from the inlet duct and air from the return duct
Implementation Method 2
a significant amount of moisture can be removed to reduce the absolute humidity of the air. This humidity condensate on a cooling coil
Implementation Method 3
a pump to pump condensate from the pan; and a sprayer coupled to the pump, the sprayer spraying condensate into an air path to increase efficiency
Implementation Method 4
a chiller system having an evaporator coupled to the cooling coil and a condenser; a condenser sprayer spraying the condensate in an air path over coils of the condenser
Data Source
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AI summary
An air conditioning system includes an inlet duct, supply duct, return duct and exhaust duct: a heat exchanger for providing heat transfer between air from the inlet duct and air from the return duct: a cooling coil position in the supply duct: a pan for collecting condensate from the cooling coil; a pump to pump condensate from the pan: and a sprayer coupled to the pump, the sprayer spraying condensate into an air path to increase efficiency of the air conditioning system.