System and method for estimating indoor temperature time series data of a building with the aid of a digital computer
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional energy audits for determining a building's thermal conductivity are costly, time-consuming, and invasive, and often result in inaccurate assessments due to physical mismeasurements and data assumptions, making it difficult to quantify energy consumption and cost savings from building shell upgrades.
Innovation Solution
A system and method using a digital computer to estimate indoor temperature time series data by empirically measuring thermal conductivity, thermal mass, effective window area, and HVAC system efficiency through short duration tests, allowing for the calculation of annual or periodic fuel consumption and net savings without the need for intrusive testing equipment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional on-site energy audit is performed to determine thermal conductivity, then building-specific parameters can be obtained, but the process becomes costly, time-consuming, and invasive
Solution Approach 1:
The patent uses a digital twin (virtual model) of the building to replicate and simulate thermal behavior, allowing thermal conductivity to be determined from operational data rather than physical measurements. This virtual copy enables accurate parameter estimation without invasive on-site testing, directly resolving the contradiction between measurement precision and time loss
Solution Approach 2:
The patent replaces mechanical/intrusive measurement systems (blower door tests, thermal cameras, physical inspections) with a computational model that processes existing operational data. The digital computer analyzes temperature, weather, and energy consumption data to derive thermal conductivity, eliminating the need for time-consuming physical audits while maintaining measurement accuracy
2Measurement precision
If conventional energy audit with intrusive testing equipment is used, then thermal conductivity can be measured, but the process becomes invasive and complex
Solution Approach 1:
The patent creates a digital replica of the building's thermal system that can be analyzed without physical intrusion. The virtual model incorporates building geometry, construction materials, and operational patterns to simulate thermal behavior, replacing complex intrusive testing equipment with straightforward data processing and computational analysis
Solution Approach 2:
The building's existing operational data (temperature readings, weather data, energy consumption) serves the dual purpose of normal operation and thermal conductivity determination. The system uses data already being collected for HVAC control to populate the digital twin, eliminating the need for separate specialized testing equipment and procedures
3Measurement precision
If numerical models are run to solve for thermal conductivity from audit data, then thermal conductivity can be calculated, but inaccuracies arise from physical mismeasurements and data assumptions
Solution Approach 1:
The patent replaces error-prone physical measurements with a computational inversion process. Instead of measuring thermal conductivity directly through intrusive tests that introduce measurement errors, the system uses the digital twin to invert operational data and calculate thermal conductivity, eliminating sources of error from physical measurement tools and human measurement techniques
Solution Approach 2:
The system continuously compares simulated temperature profiles from the digital twin with actual measured temperatures, adjusting thermal conductivity estimates to minimize discrepancies. This feedback mechanism validates and refines the thermal conductivity calculation, improving reliability by ensuring the derived parameters accurately reproduce observed building behavior
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 simplifies the calculation of fuel consumption and savings, providing accurate and efficient estimates of energy usage and cost benefits, independent of building type or occupancy, and allows for economic analysis of energy efficiency investments.
Implementation Method 1
a building model including building envelope heat transfer
Implementation Method 2
desired HVAC heating and cooling setpoints
Implementation Method 3
desired HVAC heating and cooling setpoints
Data Source
AI summary
A system and method to determine building thermal performance parameters through empirical testing is described. The parameters can be formulaically applied to determine fuel consumption and indoor temperatures. To generalize the approach, the term used to represent furnace rating is replaced with HVAC system rating. As total heat change is based on the building's thermal mass, heat change is relabeled as thermal mass gain (or loss). This change creates a heat balance equation that is composed of heat gain (loss) from six sources, three of which contribute to heat gain only. No modifications are required for apply the empirical tests to summer since an attic's thermal conductivity cancels out and the attic's effective window area is directly combined with the existing effective window area. Since these tests are empirically based, the tests already account for the additional heat gain associated with the elevated attic temperature and other surface temperatures.