Lars Ekberg - Academia.edu (original) (raw)

Papers by Lars Ekberg

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Environmental Science and Pollution Research

The main aim of this study is to develop a mathematical size-dependent vehicle cabin model for pa... more The main aim of this study is to develop a mathematical size-dependent vehicle cabin model for particulate matter concentration including PM2.5 (particles of aerodynamic diameter less than 2.5 μm) and UFPs (ultrafine particles of aerodynamic diameter less than 100 nm), as well as CO2 concentration. The ventilation airflow rate and cabin volume parameters are defined from a previously developed vehicle model for climate system design. The model simulates different filter statuses, application of pre-ionization, different airflow rates and recirculation degrees. Both particle mass and count concentration within 10–2530 nm are simulated. Parameters in the model are defined from either available component test data (for example filter efficiencies) or assumptions from corresponding studies (for example particle infiltration and deposition rates). To validate the model, road measurements of particle and CO2 concentrations outside two vehicles were used as model inputs. The simulated insi...

Over the last decades, strong focus has been placed on the energy efficiency of buildings; not le... more Over the last decades, strong focus has been placed on the energy efficiency of buildings; not least school buildings. Energy performance (EP) of buildings is nowadays in principle described by one single indicator based on purchased energy in kWh/year.m2. Another important building performance aspect is the indoor environmental quality. This study’s overarching goal is to identify school buildings with a good balance between energy performance and indoor environment. Thus, this paper investigates possible correlations between information given in energy performance certificates (EPCs/e.g. energy use, year of construction, type of ventilation) and measured indoor environmental parameters. The work comprises investigation of approximately 20 school buildings with different ventilation systems in Gothenburg. In-situ investigations of the buildings’ properties and ventilation systems were conducted. Indoor environmental parameters were recorded during one week in each classroom. In thi...

This paper presents results from a pilot thermal comfort study in five Swedish grade school class... more This paper presents results from a pilot thermal comfort study in five Swedish grade school classrooms in three different buildings during winter 2015/16. The study includes measurements of environmental parameters (air temperature, globe temperature, relative humidity, air speed, CO2) and questionnaire surveys designed to match the children’s cognitive level. The questionnaire includes questions about thermal perception, air quality and air movement, as well as the children’s clothing level. The aim of this study is to investigate whether recently found differences in thermal sensation between children and adults outside the heating season also apply to the winter season. Children’s assessment is compared to the objective measurements during the surveys, to winter design criteria for school classrooms and to comfort temperatures from previous studies. The results agree with the previously found warmer sensation of children compared to adults’ predicted thermal sensation based on th...

Sustainability, 2020

Many people spend most of their time in an indoor environment. A positive relationship exists bet... more Many people spend most of their time in an indoor environment. A positive relationship exists between indoor environmental quality and the health, wellbeing, and productivity of occupants in buildings. The indoor environment is affected by pollutants, such as gases and particles. Pollutants can be removed from the indoor environment in various ways. Air-cleaning devices are commonly marketed as benefiting the removal of air pollutants and, consequently, improving indoor air quality. Depending on the type of cleaning technology, air cleaners may generate undesired and toxic byproducts. Different air filtration technologies, such as electrostatic precipitators (ESPs) have been introduced to the market. The ESP has been used in buildings because it can remove particles while only causing low pressure drops. Moreover, ESPs can be either in-duct or standalone units. This review aims to provide an overview of ESP use, methods for testing this product, the performance of existing ESPs conc...

Environmental Science and Pollution Research, 2020

The main aim of the study was to evaluate the influence of filter status (new and aged), pre-ioni... more The main aim of the study was to evaluate the influence of filter status (new and aged), pre-ionization, on the particle filtration in modern passenger cars. Measurements of in-cabin and outside PM2.5 (dp < 2.5 μm) concentration and UFP (ultrafine particle, dp < 100 nm) counts, to calculate I/O (indoor to outdoor) ratios, were performed. They were done at two locations, to study the influence of different outside conditions on the HVAC (heating, ventilation, and air-conditioning) system. The measurements were performed in two new cars, with similar HVAC systems and settings, using a new filter and an aged synthetic filter. Furthermore, an ionization unit was installed upstream of the filter in both cars. This enabled the study of filter status, with and without ionization, under common driving conditions. The results show that the HVAC system performances were very similar at the two locations, with average I/O ratios of 0.35–0.40 without ionization and 0.15–0.20 with ionizati...

Hvac Magasin For Klima Og Energiteknik Miljo Bygningsinstalltioner Netvaerk, 2010

Miljoforskning For Ett Uthalligt Samhalle, 2002

Husbyggaren Sbr Svenska Byggingenjorers Riksforbund, 2011

Vvs Forum Specialnummer Om Ventilation Och Inneklimat, 2008

Energi Och Miljo, 2013

For nagra ar sedan horde Swegon Air Academy talas om en kand hamburgerkedja som renoverade en av ... more For nagra ar sedan horde Swegon Air Academy talas om en kand hamburgerkedja som renoverade en av sina restauranger i Stockholm. Den installerade ett FTX-aggregat tillsammans med en ozongenerator som skulle sanka kostnaden for att rensa franluftskanalen fran fett och for att skydda luftbehandlingsaggregatet. Hur skulle ozonet paverka luftens innehall av fororeningar? Vad kunde man lara sig infor nasa installation med ozon? Ozon har en stor benagenhet att reagera kemiskt med andra amnen, dels i luften, dels pa ytor. Detta utnyttjas ibland for att bryta ner fett i franluftsystem. De kemiska reaktioner som leder till renare kanaler och minskad underhallskostnad kan emellertid ocksa leda till produktion av halsoskadliga amnen, till exempel kvavedioxid och aldehyder sasom formaldehyd. Ozonet i sig utgor ocksa en halsorisk som i korthet hanger samman just med att amnet ar mycket reaktivt. Renoveringen av restaurangen i Stockholm innebar ett bra tillfalle att studera hur luftens kemiska sammansattning paverkas av denna typ av avsiktlig ozongenerering. Den har artikeln redovisar en sammanfattning av de provtagningar och kemiska analyser som genomfordes.