Design of experiments for Quick U-building method for building energy performance measurement

TL;DR

This paper presents a method to optimize the Quick U-building (QUB) energy measurement technique by analyzing the building's thermal response through a state-space model, enabling shorter experiment durations.

Contribution

It introduces a novel approach to estimate measurement error based on eigenvalue decomposition, improving the efficiency of QUB experiments.

Findings

Buildings exhibit dominant and negligible time constants affecting response.

QUB experiments can be shortened based on eigenvalue analysis.

The method enhances measurement accuracy with reduced testing time.

Abstract

Quick U-building (QUB) is a method for short time measurement of energy performance of buildings, typically one night. It uses the indoor air temperature response to power delivered to the indoor air by electric heaters. This paper introduces a method for estimating the expected measurement error as a function of the amplitude and the time duration of the input signal based on the decomposition of the time response of a state-space model into a sum of exponentials by using the eigenvalues of the state matrix. It is shown that the buildings have a group of dominant time constants, which gives an exponential response, and many very short and very large time constants, which have a small influence on the response. The analysis of the eigenvalues demonstrates that the QUB experiment may be done in a rather short time as compared with the largest time constant of the building.