A review of factors impacting exposure to PM2.5, ultrafine particles and black carbon in Asian transport microenvironments

The technological development and economic of scale for solar photovoltaic (PV), batteries and combined heat and power (CHP) have led to the technical potential for a mass-scale transition to off-grid home electricity production for a significant number of utility customers. However, economic projections on complex hybrid systems utilizing these three technologies is challenging and no comprehensive method is available for guiding decision makers. This paper provides a new method of quantifying the economic viability of off-grid PV+battery+CHP systems by calculating the levelized cost of electricity (LCOE) of the technology to be compared to centralized grid electricity. The analysis is inherently conservative as it does not include the additional value of the heat form the CHP unit. A case study for residential electricity and thermal demand in an extreme worst case environment (Houghton, Michigan) is provided to demonstrate the methodology. The results of this case study show that with reasonable economic assumptions and current costs, PV+battery+CHP systems already provide a potential source of profit for some consumers to leave the grid. A sensitivity analysis for LCOE of such a hybrid system was then carried out on the capital cost of the three energy sub-systems, capacity factor of PV and CHP, efficiency of the CHP, natural gas rates, and fuel consumption of the CHP. The results of the sensitivity provide decision makers with clear guides to the LCOE of distributed generation with off-grid PV+battery+CHP systems and offer support to preliminary analysis that indicated a potential increase in grid defection in the U.S. in the near future.

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Levelized cost of electricity for solar photovoltaic, battery and cogen hybrid systems

Solar heat pump systems (SHPs) have been investigated for several decades and have been proven to increase the share of renewable energy and reduce electric energy demand in residential heating app ...

Techno-economic review of solar heat pump systems for residential heating applications

Assessing modelled outdoor traffic-induced noise and air pollution around urban structures using the concept of landscape metrics

A systematic review of recent air source heat pump (ASHP) systems assisted by solar thermal, photovoltaic and photovoltaic/thermal sources

Four geometrical configurations of a real street canyon in Barreiro city (Portugal) are considered to study their influence on the dispersion of PM. These configurations include actual architectural layout of the street (Option 1), and three virtual cases (Options 1-3). Option 2 includes the modification of real geometry by including 4 m gaps between the buildings situated on the southern part of the street canyon. Option 3 considers 6 m gaps between buildings as opposed to 4 m gaps in Option 2. Option 4 assumes the same height for all buildings on the southern part of the street canyon, with no gaps between buildings. Computational fluid dynamics code (CFD), FLUENT, is used to simulate the detailed flow and turbulence characteristics in three-dimensional domain of chosen street canyon, together with the PM dispersion for both the summer and winter seasons. The modelled PM concentrations were then compared with the measured data at seven different locations in the street canyon. Our results indicate up to 23% lower PM concentrations at 1.5 m above the road level during the along-canyon wind direction due to the channelling of flow, compared with those observed during the cross-canyon wind direction. Detailed inspection of the results obtained from the Options 1-3 indicated that the spacing between the buildings tend to increase particle dilution during the cross-canyon winds, resulting in up to 20, and 22% reduced concentrations for options 2, and 3 respectively, compared with the actual configuration (Option 1). The largest improvement (∼7%) in the PM concentrations was given by Option 2, while other options showed modest changes. Possible reasons for these changes under varying meteorological conditions are explained in the context of changing building configurations and their implications in city planning. © 2013 Elsevier Ltd. All rights reserved.

https://www.gracacarvalho.eu/xms/files/BIOGRAFIA/PUBLICACOES/Artigos_em_Revistas_Internacionais/urban_climate_2013.pdf

Influence of virtual changes in building configurations of a real street canyon on the dispersion of PM10

A solar trigeneration system, based on photovoltaic-thermal (PV/T) collectors, photovoltaic (PV) modules and a heat pump unit for heating and cooling, is modelled to forecast the thermal and electric yields of the system. The aim of the trigeneration system is to provide enough electricity, domestic hot water (DHW), heating and cooling power to meet the typical demand of an urban single family dwelling with limited roof area and allow the household to achieve a positive net energy status. The PV/T collectors and PV modules provide the electricity while the former also powers the DHW component of the trigeneration system. The heating and cooling components rely on a vapour compression cycle heat pump unit powered by electricity. In Fong et al. (2010), solar-powered electric compression refrigeration was found to have the most energy saving potential in subtropical climates. Thus, a heat pump based cooling system is a cost effective solution for residential applications in Lisbon, Portugal. Thus, according to the dwelling's location, construction details and energy demand patterns, the model computes the system's net results by comparing the dwelling demand with the trigeneration system supply. The paper presents a breakdown of the proposed trigeneration system model and describes each component briefly. Preliminary results produced by the model are presented and analysed in order to identify possible ways of improving the overall system performance.

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A PV/T and Heat Pump based trigeneration system model for residential applications

A solar trigeneration system for off-grid households, based on photovoltaic-thermal (PV/T) collectors, photovoltaic (PV) modules and a heat pump (HP), whose aim is to provide enough electricity, domestic hot water (DHW), heating and cooling power to meet the typical demand of an offgrid single family dwelling, is modeled to predict its performance, enable system sizing and evaluate the impact of different control and management strategies. The system integrates an autonomous photovoltaic system, a solar DHW system and a heating, ventilation and air-conditioning (HVAC) system. Thus, according to local climate data, construction elements, load profiles and storage dynamics, the model computes the system’s net results using a simple supply and demand approach. Additionally, a design space methodology is used to evaluate system performance for different sizes and identify a feasible design region within which reliable and cost-effective system sizing is possible.

/pdf/solar-trigeneration-system-model-for-off-grid-residential-29c40vpp72.pdf

Solar Trigeneration System Model for Off-Grid Residential Applications

This paper intends to show the influence of street geometry in particle concentration emitted from traffic source, on a busy street of Barreiro City, Portugal. FLUENT software was used to simulate particle dispersion, air flow and turbulence in the street. Buildings and road characteristics were considered, as well as winter and summer most predominant meteorological conditions. Also, particle concentrations were measured. The results show that when street orientation is equal to wind orientation, a good dispersion is promoted and low particle concentrations are achieved. Concerning the effect of building height, some recirculation is noticed affecting mainly the residents. In this street geometry north wind direction promotes some positive recirculation raising wind velocity and pollutant dispersion, while the effect of south winds is negative since the wind speed is lower, trapping particles. Considering some differences in the geometries it was possible to conclude that some gaps between buildings could help pollutants’ dispersion.

/pdf/studying-street-geometry-influence-in-pm-10-concentration-3ooyipy2j9.pdf

Studying street geometry influence in PM 10 concentration

This article studies the influence of building street geometry, wind direction, daily car traffic and pedestrian trajectories in short-term personal exposure to PM10 on a street canyon in Barreiro City, Portugal. An automatic system for the analysis of traffic profiles, a Gaussian model for the determination of traffic emissions (ADMS- Urban) and a computational fluid dynamics model (ANSYS Fluent) to simulate the dispersion of pollutants inside a street canyon were used. Buildings height, width, length and geometry, as well as the distance between the buildings and road width were tested. Besides the real actual geometry of the street, with the real disposition and volumetric configuration of buildings, three scenarios were evaluated: (i) gaps of 4 m between the buildings along the street; (ii) gaps of 6 m between the buildings along the street and (iii) same height and width for all buildings along the street without gap between buildings. Wind direction, wind velocity and four pedestrian trajectories were considered. The results show that PM10 concentration, at 1.5-m high plane, is highly dependent on street geometry and wind conditions for along-canyon wind directions (west and east wind). Lower concentration levels are obtained for configuration (iii) because this geometry promotes the dispersion of pollutants under along-canyon wind direction. For cross-canyon wind directions (north and south), configuration (i) results in lower PM10 concentrations. There are no visible improvements in having higher gaps between buildings (configuration ii). Short-term pedestrian personal exposure is dependent on the pedestrian trajectory considered inside the canyon. Pedestrian trajectories that correspond to crossing the road in the centre of the street result in the highest values. Keywords Air quality, PM10, short-term personal exposure, street canyon, urban planning Language: en

/pdf/analysis-of-pedestrian-short-term-exposure-on-a-high-traffic-3wifffslpb.pdf

N. Tavares

Papers

Influence of virtual changes in building configurations of a real street canyon on the dispersion of PM10

A PV/T and Heat Pump based trigeneration system model for residential applications

Solar Trigeneration System Model for Off-Grid Residential Applications

Studying street geometry influence in PM 10 concentration

Analysis of pedestrian short-term exposure on a high traffic city street