From single tests to a test-chain: A comprehensive approach for evaluating the interaction between the building envelope and the IEQ

In recent years building envelope systems have become increasingly more com-plex. Especially in high-performance low-carbon buildings, envelopes comprise several passive and active components such as advanced membranes, mechanical ventilation machines and integrated photovoltaics that must be mutually optimized to ensure a global elevated performance. One of the key expectations from these innovative envelopes is better capabilities of providing highly comfortable and healthy indoor environments while using as little energy as possible. However, the complexity of such envelopes poses two major challenges: (i) standard assessment procedures might not be usable to evaluate them either because these do not fully capture their potential or be-cause the complexity of product makes the standard test unfeasible, and (ii) multiple indoor environmental quality (IEQ) domains are simultaneously affected by these envelopes, and thus complementary tests in different domain are needed to ensure that a benefit in one domain does not lead to issues in others. For this reason, a test-chain for a thorough energy demand, indoor occupants' comfort, and behaviour analysis performance has been implemented. It comprises a set of labs and additional simulation capabilities to study the building envelope-IEQ interaction at various technology readiness level. This paper provides an overview of the test-chain and its first application for the evaluation of a multifunctional facade. This facade includes a reversible air-to-air heat pump, a mechanical ventilation system, and openable windows, and aims at easing the achievement of the nZEB target while delivering elevated IEQ.