Evaluation tool of climate potential for ventilative cooling

Abstract

The ventilative cooling potential tool (VC tool) aims at assessing the potential effectiveness of ventilative cooling strategies by taking into account also building envelope thermal properties, occupancy patterns, internal gains and ventilation needs. The analysis is based on a singlezone thermal model applied to user-input climatic data on hourly basis. For each hour of the annual climatic record of the given location, an algorithm identifies over the occupied time the number of hours when ventilative cooling is useful and estimates the airflow rates needed to prevent building overheating. As validation of results, the ventilative cooling potential tool outputs are compared with the predictions of a building energy simulation model of a reference room in two different climates. The VC tool is particularly suitable for early design phases, providing building designers with useful information about the level of ventilation rates needed to offset given rates of internal heat gains.

Open-plan office design for improved natural ventilation and reduced mixed mode supplementary loads

“…In the warm period, the prediction difference between the two methods does not exceed a day, specifically 16 h. The total number of office working hours in the studied months is 1056 h. Accordingly, the simulation model and VC method predict 622 and 638 h of comfort, respectively, corresponding to 58.9% and 60.4%. In reference to findings of a study, 50 which claims that the VC method overestimates the number of comfort hours for direct VC, the comparatively lower number of comfort hours predicted by the simulation analysis method in May, June, July and September can be considered as reasonable. In addition, the VC method uses a standard comfort zone for its evaluation criteria, in which the upper limit does not change in accordance with the outdoor temperatures.…”

“…Nevertheless, the ventilative cooling method 49,50 was used – as an ‘objective validation technique’ of the mathematical procedure 51 – to validate dynamic simulations of indoor environment calculations on an hourly basis.…”

“…Derived from the National Institute of Standards and Technology 49 and further developed within the framework of International Energy Agency Annex 62, 50 the VC method was utilised to validate NV performance relative to comfort hours predicted by dynamic building simulation. The emergence of this method refers to the continuous interest towards low energy buildings The algorithmic model processes hourly annual climatic conditions, taking into account the intended TC criteria.…”

Opportunities and pitfalls of using building performance simulation in explorative R&D contexts

“…location) in which the technology has the highest potential (Hensen et al 2015). Climate scoping studies such as the work by DeForest et al (2013), Causone (2016), Belleri et al (2018), andJuaristi et al (2018) can be carried out, but there is little guidance about how such studies are best performed.…”

Correlation of Ventilative Cooling Potentials and Building Energy Savings in Various Climatic Zones

“…The index represents the climatic condition for passive cooling systems depending on the airflow rate, the comfort set point, and various building characteristics. In the Annex 62 project, experts from 13 countries developed a VCP tool to assess the VCPs considering the building characteristics, loads, and ventilation systems [8].…”