Dynamic metrics of natural ventilation cooling effectiveness for interactive modeling

Abstract

The evaluation of natural ventilation potential for cooling indoor spaces during the early design phases is of great interest to researchers and practitioners. Among various definitions and usages for natural ventilation potential (NVP) in early design evaluation, this paper reviews and identifies the key performance indicators, and proposes two new dynamic metrics-natural ventilation cooling effectiveness (NVCE) and climate potential utilization ratio (CPUR). The metrics 1 are dynamically responsive to various design options, in both steady and transient states, allowing consideration of thermal mass. Assisting in design development processes, the metrics quantify how well indoor spaces make use of natural ventilation's cooling capacity. Case studies are presented to demonstrate how NVCE and CPUR enable designers to evaluate the predicted performance and how to apply the information to improve building design. The results of the design iterations showed that the relationship among various design parameters should be dynamically understood in order to evaluate the performance of natural ventilation, confirming that "the more the airflow, the greater the potential," and "the heavier the thermal mass, the greater the energy saving" were not always true.

Natural Ventilation Cooling Effectiveness Classification for Building Design Addressing Climate Characteristics

“…Building uncertainties arise mainly from the possible variation of material properties and approximation of physical processes in the building simulation. Nari Yoon [34] proposes two new metrics (NV cooling effectiveness and climate potential utilization ratio) for dynamic response to various design options in both steady and transient states, allowing consideration of thermal mass. Cristina Baglivo studied how envelope design optimization impacts a building's thermal behavior in a certain warm climate [35].…”

Impact of climate change on the potential of free-cooling strategies for a retrofitted building in a hot climate

“…• The air temperature and the average radiant temperature are the two parameters used for evaluating the thermal conditions. The combination of these two temperatures gives the operative temperature, which is calculated from equation (8).…”

“…7 However, understanding a climate's potential for natural ventilation should be the first step. A comprehensive review of natural ventilation metrics was presented by Yoon et al 8 The three leading performance indices identified by the authors are the Climatic Potential for Natural Ventilation (CPNV), the Natural Ventilation Cooling Effectiveness (NVCE) and the Climate Potential Utilization Ratio (CPUR). This study also demonstrated the applicability of these measures in a design procedure:…”

“…7 However, understanding a climate’s potential for natural ventilation should be the first step. A comprehensive review of natural ventilation metrics was presented by Yoon et al 8 The three leading performance indices identified by the authors are the Climatic Potential for Natural Ventilation (CPNV), the Natural Ventilation Cooling Effectiveness (NVCE) and the Climate Potential Utilization Ratio (CPUR). This study also demonstrated the applicability of these measures in a design procedure:- During the site assessment phase, the CPNV gives general ideas about the cooling potential that the site can provide.- During the design development phase, the NVCE provides the key information about the cooling efficiency of a given design solution.…”

Influencia del microclima en el confort térmico y desempeño energético de las edificaciones: Evaluación numérica del asentamiento de un patrimonio histórico.

“…The NVCP was used as one of the indicators for assessing ventilation potential. This indicator is based on air temperature and relative humidity (Yoon, Norford, Malkawi, Samuelson, & Piette, 2020).. It is defined as the number of hours within a stipulated time range.…”