90.1-2019 Building descriptors will be added to define how VRF systems can be modeled for the proposed design. Variable refrigerant flow systems are not applicable to the baseline building system. Book traversal links for 3.7.5.9 Variable Refrigerant Flow ‹ 3.7.5.8 Ground-Source Heat Pumps Up 3.7.5.10 Underfloor Air Distribution ›