Variable refrigerant package
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Solution Overview
Problem
Conventional through-the-wall air conditioning units, such as PTACs and VPACs, fail to effectively ventilate and dehumidify spaces, leading to humidity issues and musty smells, especially in coastal areas, and require additional complex and expensive systems or ductwork for proper dehumidification.
Innovation Solution
A variable refrigerant package with a control system that dehumidifies outside air before introducing it into the space, using pulse width modulation to adjust compressor and fan power, and incorporating a reheat system for enhanced dehumidification, allowing for easy installation by non-skilled personnel and reducing power consumption through active power factor correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional PTAC/VPAC units are used for cooling, then the space temperature is satisfied, but humidity builds up and dehumidification is insufficient
Solution Approach 1:
The system dynamically adjusts refrigerant flow to evaporator coils using electronic expansion valves, allowing continuous modulation of cooling capacity. This enables the system to maintain temperature while providing sufficient run time for dehumidification, resolving the contradiction between temperature satisfaction and humidity control
Solution Approach 2:
The system changes operational parameters by independently controlling multiple evaporators with variable refrigerant flow. By adjusting refrigerant flow rates and evaporator activation sequences, the system achieves both temperature maintenance and effective dehumidification that conventional single-stage systems cannot provide
2Object-affected harmful factors
If separate dehumidifiers or duct work are added to PTAC/VPAC units, then dehumidification capability is improved, but device complexity and installation difficulty increase
Solution Approach 1:
The system merges dehumidification and ventilation functions into the base unit itself by incorporating multiple evaporators that can be independently controlled. This integration eliminates the need for separate dehumidifiers and complex duct work, reducing overall system complexity while maintaining effective humidity control
Solution Approach 2:
The base unit is designed with multi-functionality, serving as cooling, dehumidification, and ventilation equipment simultaneously. The variable refrigerant flow system can operate in different modes (cooling only, dehumidification, ventilation) by adjusting evaporator configuration, providing universal functionality without additional devices
3Ease of operation
If outside air is brought in through PTAC flap, then ventilation is provided, but humidity is introduced causing musty smell
Solution Approach 1:
The system performs preliminary dehumidification of outside air by running the evaporator before introducing the air into the conditioned space. This preliminary action removes excess moisture from ventilation air, preventing the musty smell problem while maintaining ventilation benefits
4Power
If variable refrigerant flow systems with large outdoor condensers are used, then cooling capacity is improved, but humidity control and ventilation remain problematic
Solution Approach 1:
The system segments the refrigeration system into multiple independent evaporators with individual electronic expansion valves. This segmentation allows independent control of refrigerant flow to each evaporator, enabling precise control over cooling capacity and dehumidification performance, resolving the humidity control issues in conventional VRF systems
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
The system effectively dehumidifies and ventilates enclosed spaces, reducing humidity and musty smells, while being easy to install and energy-efficient, addressing the limitations of traditional air conditioning units by providing stable and variable power to the refrigerant package.
Implementation Method 1
the condensate water extracted from the air by the evaporator coil
Implementation Method 2
the condenser fan onto the condenser coil surface where it evaporates
Implementation Method 3
the condensate water extracted from the air by the evaporator coil is thrown by the condenser fan onto the condenser coil surface where it evaporates
Data Source
AI summary
A variable refrigerant package air conditioner is shown that is easy to install in new construction with a unique base that causes collected mixture that overflows to drain outside the building. A control system is shown that has motors and compressor that are pulse width modulated so the air conditioner is infinitely variable while maintaining the highest possible power factor. Dehumidification of outside air occurs as it is mixed with inside air. By gradually approaching a temperature set point and even reheating after dehumidification, moisture is removed from the room.