Review of In-situ Building Envelope Measurement Techniques

Integrated building performance monitoring through sensors and instruments is the current need of building engineering and sciences for retrofitting, optimizing, and future design works. Despite various simulation engines and laboratory test results, the on-site performance of building components is vastly different from the predicted and laboratory performance. Variable climatic conditions, moisture, and time influence it. This paper provides crucial insights into the monitoring methods for integrated performance assessment of buildings as per heat, mass, and light aspects of performance laid out by IEA Annex 32. The paper analyzes the existing methods without a large setup requirement for accuracy in the results of these aspects, considering many input parameters of applicability. It presents a comparative analysis of the three most commonly used measurement techniques of thermal transmittance of heat flux, thermometry, and infrared and recommends applying appropriate techniques for accurate results. The state of knowledge currently resides in the use of in-situ measurements, but without comprehensive understanding of boundary conditions, sensor characteristics, response time, application requirements, pasting requirements, sensitivity analyses, and selection of sensors as per the local context. The paper will help to take up integrated real-time assessment through the knowledge of the techniques, types of equipment required, available, and set-up requirements. Detailed analysis of U value measurements, application per certain wall surface conditions, and prominent factors for accurate results are deduced for heat flux, thermometric, and infrared thermography methods. Future work lies in the potential integration of continuous monitoring approaches and statistical computing with energy modeling and techniques that provide rational solutions for design and optimization and relate to time-weighing functions to increase the scalability to different system levels.