Apparent Temperature Thermostat for Humidity-Aware HVAC Switchover

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Conventional HVAC systems fail to account for factors like relative humidity and radiative heat transfer, leading to discomfort for occupants and inefficient energy use, as they only regulate temperature without considering these variables.

Innovation Solution

A climate control system that includes temperature and humidity sensors, a processor, and a non-transitory computer-readable storage medium with software instructions to calculate apparent temperature and automatically switch between heating and cooling modes based on user-selected desired apparent temperature, using semi-empirical algebraic equations and polynomial equations to adjust both dry bulb temperature and relative humidity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If conventional HVAC systems only regulate temperature, then the system complexity is low, but occupant comfort deteriorates due to ignoring humidity and radiative heat transfer

Engineering Contradiction:
Improvesystem complexityVSAvoidoccupant comfort
Core Design Contradiction:
Device complexityVSEase of manufacture

Solution Approach 1:

The patent transforms the control parameter from simple dry bulb temperature to apparent temperature, which is calculated from temperature and humidity measurements. This parameter change allows the system to account for humidity effects on comfort without requiring complex hardware modifications, thereby improving comfort while maintaining relatively simple system architecture.

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If HVAC systems account for relative humidity and radiative heat transfer, then occupant comfort is improved, but device complexity increases

Engineering Contradiction:
Improveoccupant comfortVSAvoidsystem complexity
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent introduces apparent temperature as an intermediary parameter that mediates between the simple temperature measurement and the complex combination of temperature, humidity, and radiative heat transfer effects. By using this intermediary, the system captures the combined effects of multiple factors without directly measuring or controlling each factor separately, thus improving comfort while avoiding excessive system complexity.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system changes the control parameter from temperature alone to apparent temperature, which incorporates humidity effects through a mathematical relationship. This allows the system to respond to humidity-induced discomfort without requiring complex humidity control hardware, achieving improved comfort with minimal increase in device complexity.

Inventive Principle:
Principle #35Parameter changes

3Use of energy by moving object

If conventional thermostats maintain set temperature without considering humidity, then energy use is simple to control, but comfort deteriorates leading to inefficient energy use

Engineering Contradiction:
Improveenergy control simplicityVSAvoidenergy efficiency
Core Design Contradiction:
Use of energy by moving objectVSProductivity

Solution Approach 1:

The patent implements feedback control based on apparent temperature, which incorporates humidity measurements into the control decision-making process. The system continuously monitors temperature and humidity, calculates apparent temperature, and adjusts HVAC operation accordingly. This feedback mechanism ensures energy is used efficiently by responding to actual comfort conditions rather than temperature alone, preventing wasted energy on cooling when high humidity already causes discomfort.

Inventive Principle:
Principle #23Feedback

4Ease of manufacture

If more complex HVAC systems adjust both temperature and relative humidity, then comfort is improved, but cost increases due to humidifiers, dehumidifiers, and reheat systems

Engineering Contradiction:
Improvecomfort levelVSAvoidsystem cost
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent changes the control parameter from temperature alone to apparent temperature, which mathematically incorporates humidity effects. This allows the system to respond to humidity-induced discomfort by adjusting temperature setpoints rather than directly controlling humidity. Consequently, the system achieves improved comfort without requiring expensive humidifiers, dehumidifiers, or reheat systems, avoiding the need for complex multi-component hardware while still addressing humidity-related comfort issues.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3695287B1An automatic switchover thermostat system based on apparent temperature and method for determining and automatically controlling the apparent temperature of a conditioned space
Publication Date: 2024.04.17 ASSOUAD BECHARA PHILIPPE
  • EP3695287B1 patent drawingFigure 1A~1B
  • EP3695287B1 patent drawingFigure 2A
  • EP3695287B1 patent drawingFigure 2B

AI summary

A climate control unit configured to control a heating unit and a cooling unit. The climate control unit includes a temperature sensor configured to measure a current dry bulb temperature, a humidity sensor configured to measure a current relative humidity, a processor, and a storage medium operably coupled to the processor. The storage medium has software instructions stored therein, which, when executed by the processor, cause the processor to determine a current apparent temperature based on the current dry bulb temperature and the current relative humidity, receive a user-selected desired apparent temperature, activate a heating mode when the current apparent temperature is below a lower apparent temperature threshold, and activate a cooling mode when the current apparent temperature is above an upper apparent temperature threshold. The software instructions, when executed by the processor, cause the processor to automatically switch between the heating mode and the cooling mode.