Paul D. O'Sullivan

Munster Technological University | MTU

The Grid Convergence Index (GCI) method requires at least three systematic mesh refinements, each requiring the numerical solution to be in the asymptotic range. When the observed order of accuracy differs from the formal order of accuracy, a lack of numerical precision exists which may result in erroneous conclusions. The aim of the work in this p...

The average global cooling demand in non-residential buildings is expected to increase by over 275% between now and 2050. Controlled passive cooling is fundamental to successful operational performance of buildings and in mitigating energy that would otherwise be consumed by mechanical systems. The aim of this study was to determine the resilience...

This paper presents an energy performance comparison of air to water heat pump manufacturer quoted values, calculated seasonal performance values from standards and actual in-use values for space heating mode only. Within this, the paper determines whether an in-use factor would be suitable to correct performance predictions where differences exist...

Natural ventilation (NV) through a single openable window (SS1) is the most common passive cooling strategy for small rooms. SS1 NV driven by wind can be propelled by pressure variations along the opening or, in medium and large buildings, wind driven shear. This paper presents an experimental study of the impact of typical window geometries on SS1...

Wind-driven single-sided ventilation (SSV) is present in many existing buildings across Europe, and with new near-zero energy building (NZEB) regulations for the refurbishment of the existing building stock, its attractiveness as a noninvasive, low-energy solution is set to continue. As a strategy, however, in addition to its air change rate capaci...

Wind-driven single-sided ventilation is present in many existing buildings globally, and its performance can be unreliable and challenging to improve. To address these performance challenges, a better understanding of the interconnected relationship between the external and internal flows is required. Therefore, a detailed assessment of this type o...

There is a continued need to improve the energy (and by extension carbon) performance of the existing building stock in Europe and globally. Recent experiences with the COVID-19 pandemic have demanded even more of the built environment disciplines when it comes to air quality and ventilation rates particularly in teaching environments which are see...

Mitigating the risk of overheating and associated thermal discomfort inside school classrooms is a global concern due to its significant impacts on students' academic performance, health and wellbeing. Thus, rising ambient temperatures resulting from climate change can be challenging, especially in low energy schools designed to optimise their heat...

The use of the word "resilience" has increased significantly since 2010, however, there is a lack of understanding around 1) how thermal resilience is defined (where some definitions were offered only recently) and 2) what distinguishes it from typical overheating assessments. In addition to this, there is a lack of uptake in the remote monitoring...

The global COVID pandemic has seen a significant change in ventilation practices, where the need to ventilate buildings has been put centre stage. Longer-term ventilation approaches are likely to incorporate hybrid ventilation strategies to deal with the multi-objective challenge of enhanced comfort resilience in the face of a warming climate but m...

The quality of future working circumstances for many will be contingent on how low energy indoor spaces respond to challenges from accelerated ambient warming. Resilient cooling is increasingly relevant given the need to evaluate whether a building designed today is resilient against extreme disturbances to the thermal environment from events in th...

Increasing participation in demand response within the industrial sector may be crucial to growing the levels of available flexible capacity required to reliably control national electricity grids as renewable generation increases to satisfy emission targets. This research aims to assist the uptake of demand response in the industrial sector by inv...

This chapter describes how to integrate and use ventilative cooling (VC) in residential buildings. A large set of case studies is introduced and classified in order to better define solutions for different climate and residential building typologies. Furthermore, the potential effect of ventilative cooling is analysed while design choices and techn...

Integrated units that combine Exhaust Air Heat Pumps (EAHPs) with Heat Recovery Ventilation (HRV) and, in some instances, Domestic Hot Water Storage (DHW), are becoming increasingly popular in the domestic market across Europe with over 24,000 EAHPs purchased in the EU in 2017 alone. Early research into using EAHPs demonstrated energy savings being...

There is an expectation in the design of buildings that installed ventilation systems are energy efficient, adequately sized, and, have appropriate controls. Equally, there is an expectation that occupants should be given sufficient information about these systems and how they are controlled. There is also an expectation that during operation mecha...

In this study, a grey box (GB) model for simulating internal air temperatures in a naturally ventilated nearly zero energy building (nZEB) was developed and calibrated, using multiple data configurations for model parameter selection and an automatic calibration algorithm. The GB model was compared to a white box (WB) model for the same application...

There has been a recent focus on the gap between actual and predicted energy performance of our buildings, known as “the performance gap”. Inaccurately matching designed energy consumption with the actual energy consumption of a building could result in member states not reaching the strict targets that have been set for the built environment. This...

As the cooling energy demand in buildings is set to increase dramatically in the future, the exploitation of passive solutions like natural ventilation could prove vital in reducing the reliance on mechanical systems. Models that can predict air temperature accurately in naturally ventilated mode are key to understanding the potential of natural ve...

Examples of well documented case studies that use Ventilative Cooling (VC) to reduce the energy demand for cooling or overheating risk in new and refurbished buildings are valuable to the energy in buildings community. This report and associated brochures contains such examples and provides details on the design, control, operation and performance...

Even in Northern European climates, overheating in many Nearly Zero Energy Buildings is a barrier to year round occupant satisfaction with the indoor thermal environment. Improved energy performance and enhanced thermal comfort should not be perceived as a rigid dichotomy of concepts. However, an acceptable thermal environment, during extended cool...

During cooling seasons, a progressively warmer and increasingly urban world is leading to hostile internal thermal environments in many high-performance buildings. Correctly Implemented, Ventilative Cooling can mitigate unwanted building overheating while minimising cooling loads. Identifying different solutions with proven performance can be inval...

Overheating is an unwanted consequence of modern building designs and internal gains that will be aggravated by the effects of climate change on local climates within urban and suburban areas. To minimise the energy cost of limiting overheating several different approaches exist for passive cooling dissipation techniques. Free cooling by ventilatio...

Robust retrofitting is integral to reducing the energy consumption of the existing building stock. Simulation plays a key role in determining the most effective retrofit solution for a particular building. While many synthetic test cells provide an environment to validate whole building simulation tools, calibration reflects the real operation of b...

Developing representative archetypes using a bottom up approach for stock modelling is an excellent tool for evaluating the overall performance of the building stock; however it requires detailed analysis of the various building types. Currently there is no detailed housing data base for Local Authority housing in Ireland that catalogues the housin...

In this study, the effectiveness of a retrofitted natural ventilation system in a low energy building was evaluated, both subjectively and objectively, in response to an overheating scenario during shoulder seasons. Four ventilation configurations were evaluated including one control (no ventilation) configuration. Standardised questionnaires were...

Traditional surveying of building façades through direct measurement are time consuming and expensive to carry out and can breach home owner privacy. Replacing direct measurement methods with a remote method allows for the rapid extraction of façade information. The aim of the research presented in this paper was to remove the need for physical sit...

Abstract Recent scientific studies have investigated different variables may influence particulate levels in indoor environments using Computational Fluid Dynamics (CFD). These studies often adopt one or more variables and focus on the effect of these variables independently. The aim of this paper is to present a generalised approach to the develop...

Ensuring optimal thermal comfort performance in low energy building retrofits during the shoulder and summer months is challenging. One of the reasons for this is overheating due to internal and solar heat gains. The prompt removal of this trapped heat, using natural ventilation only, is critical to ensuring adequate levels of thermal comfort in bu...

Adopting natural ventilation as a low impact retrofit strategy for space cooling is attractive due to the cooling potential of untreated outdoor air for large periods of the extended cooling season, particularly in northern climates. Furthermore, it is important to characterise the performance of natural ventilation components in successfully trans...

The aim of this paper was to develop a virtual laboratory simulation platform of the National Building Retrofit Test-bed at the Cork Institute of Technology, Ireland. The building in question is a low-energy retrofit which is provided with electricity by renewable systems including photovoltaics and wind. It can be thought of as a living laboratory...

Ventilative cooling coupled with exposed thermal mass is widely accepted as an important strategy for reducing summer overheating in non-domestic buildings. Extended monitoring has shown that naturally ventilated buildings typically use less than 50% of the corresponding energy consumption of air conditioned buildings and assessment of ventilative...

Developing representative archetypes using a bottom up approach for stock modelling is an excellent tool for evaluating the overall performance of the building stock; however it requires detailed analysis of the various building types. Currently there is no detailed housing data base for Local Authority housing in Cork City, Ireland that catalogues...

Non-invasive, scalable, building retrofit solutions are very attractive deep renovation techniques to improve energy efficiency in existing buildings; this includes natural ventilation for cooling due to the low impact nature of the installation. However, a number of criteria that are important to natural ventilative cooling strategies can be subst...

Non-invasive, scalable, building retrofit solutions are amongst the most likely large scale adoption techniques to assist in climate change adaptation in the existing built environment, particularly in university type buildings where rehousing live activities will prove costly. Natural ventilation is an attractive retrofit strategy due to the low i...

The main objective of this paper is to present findings from verification of a multiphase flow Computational Fluid Dynamics (CFD) simulation of pharmaceutical cleanroom class C by adopting a grid refinement method to assess Particle Deposition Fraction (PDF) and velocity fields. Often PDF as opposed to velocity field is the parameter of interest in...

This paper reports on the design, manufacture and installation of an externally applied, modular building envelope retrofit solution for existing buildings. The paper is based on a recently completed pilot project at Cork Institute of Technology. The building that the retrofit solution was applied to is a low rise grid optimised modular concrete st...