Low/Zero-Carbon Buildings for a Sustainable Future

Fossil fuel-based energy consumption is still dominant in the world today, and there is a consensus on the limited reserves of these energy resources. Therefore, there is a strong stimulation into clean energy technologies to narrow the gap between fossil fuels and renewables. In this respect, several commitments and codes are proposed and adopted for a low energy-consuming world and for desirable environmental conditions. Sectoral energy consumption analyses clearly indicate that buildings are of vital importance in terms of energy consumption figures. From this point of view, buildings have a great potential for decisive and urgent reduction of energy consumption levels and thus greenhouse gas (GHG) emissions. Among the available retrofit solutions, greenery systems (GSs) stand for a reliable, cost-effective and eco-friendly method for remarkablemitigation of energy consumed in buildings. Through the works comparing the thermal regulation performance of uninsulated and green roofs, it is observed that the GS provides 20°C lower surface temperature in operation. Similar to green roofs, vertical greenery systems (VGSs) also reduce energy demand to approximately 25% as a consequence of wind blockage effects in winter. Therefore, within the scope of this chapter, GSs are evaluated for a reliable and effective retrofit solution toward low/zero carbon buildings (L/ZCBs)

Valutazione delle prestazioni fluidodinamiche di un catamarano con metodologie CFD in differenti configurazioni

Nel presente lavoro di tesi viene sviluppata una procedura generale per la simulazione CFD delle forze fluidodinamiche agenti sullo scafo del catamarano Dianae, durante la navigazione a differenti velocità e in presenza di mare calmo. Lo scopo principale di questo elaborato è stato quello di analizzare e successivamente migliorare la geometria dello scafo di Dianae, un innovativo catamarano dislocante, caratterizzato da una asimmetria interna dei due semi-scafi nella direzione longitudinale; tale asimmetria è data da una superficie esterna piana e una superficie interna formante un canale convergente-divergente. Si evidenzia che lo studio effettuato non tratta l’imbarcazione nella sua totalità, ma si pone lo scopo di indagare le forze fluidodinamiche agenti solamente sul corpo dell’imbarcazione (senza prendere in considerazione la sovrastruttura). L’obiettivo di tale procedura è quello di determinare una nuova geometria dello scafo tale da minimizzare la forza di resistenza all’avanzamento e di risolvere i problemi riscontrati sulla geometria assegnata in partenza. Le geometrie CAD dell’imbarcazione sono state realizzate mediante il software CATIA® V5R21 della Dassault Systemes. Per le analisi fluidodinamiche delle varie configurazioni di prova si è utilizzato Star-CCM+® v10.04.008 R8 della CD-adapco

A smart building material for low/zero carbon applications: heat insulation solar glass—characteristic results from laboratory andin situtests

Heat insulation solar glass (HISG) is a recently developed smart building material to minimize energy consumption of building sector. HISG might be presumed to be a conventional photovoltaic glazing product; however, it is completely unique by having some characteristic features such as superior thermal insulation, which is competitive with triple-glazed windows using argon as inert gas, acoustic and thermal comfort, self-cleaning ability owing to TiO2 nano-coating on module surface and extraordinary energy saving potential in both summer and winter. In our previous works, comprehensive experimental and numerical works have been carried out for power generation and thermal insulation performance of HISG under various climatic conditions. Within the scope of this research, optical- and lighting-related performance parameters of this smart building material are evaluated through extensive laboratory and in situ tests. Shading coefficient, visible light intensity, and UV and IR penetration are investigated via the tests conducted in real operating conditions. It is achieved from the results that the shading coefficient of HISG is only 0.136, which yields almost 80% reduction in solar heat gain compared with ordinary glazing. It is also observed from the in situ tests that HISG has a %100 UV and 99% IR blocking rate, which is of vital importance in terms of human health and thermal comfort conditions. Glaring effects are totally resolved via HISG, which is still a challenge for the buildings with conventional glazing products, especially in summer

Performance Analysis of Fresnel Lens Driven Hot Water/Steam Generator for Domestic and Industrial Use: A CFD Research

In this study, the design, manufacture and thermal performance analysis of a Fresnel lens driven hot water/steam generator are presented. The designed system is suitable for domestic and industrial hot water/steam usage and can be easily scaled up to meet different capacity needs. In the first step of the research, thermal behaviour of the cast plate heat exchanger driven by a Fresnel lens with a concentration ratio of 100 is investigated at different working fluid velocities (0.6, 0.8, 1.0, 1.5 and 2.0 m/s) and at different absorber surface temperatures (700, 800, 900 and 1000 °C). Outlet temperature of working fluid from the cast plate heat exchanger is determined through a 3D CFD model for each case. The capacity of the steam generator for different operating times (h = 1, 2 and 3 hours) is also evaluated. The highest working fluid temperature at the outlet of heat exchanger is 914.8 °C for T_cp= 1000 °C and V_wf = 0.6 m/s. On the other hand, the lowest temperature is observed as 424.7 °C for T_cp = 700 °C and V_wf = 2.0 m/s. The steam capacity of the system for h = 3 hours is determined as 1696.5 and 508.9 kg in the best (V_wf = 2.0 m/s) and worst cases (V_wf = 0.6 m/s), respectively

Investigation on the performance of air source heat pump system with new environment friendly refrigerants for a low carbon building

Energy is an important development factor. It is consumed in different format from different sources in daily human activities. Solar energy, as the most fundamental renewable energy resource, serves in a clean, domestic and environmentally friendly way with minimum impact on surroundings. Due to the ability of transferring heat from low temperature to high temperature, heat pump systems can make great use of natural resources and waste heat resources for the purpose of space heating. Based upon this theoretical principle, this paper presents an investigation on the performance of air source heat pump (ASHP) system with new environment friendly refrigerants, such as R1233zd(E), R1234YF, R1234ze(Z) and R1234ze(E). At the same time, some conventional refrigerants (R134a, R245fa and R123) have been investigated as well for results comparison. A MATLAB program has been developed with the assistance of the database of CoolProp. The results show that the use of some selected environment friendly refrigerants in air source heat pump system for building application alongside other refrigeration applications in strongly recommended

Theoretical investigation of soil-based thermal energy storage system for greenhouses

In this short communication, a novel thermal energy storage system for greenhouses is presented. The novel system is based on directly heating a particular mass of soil through the solar power and utilizing the energy stored in critical months such as November, December, January and February. The target mass of soil is placed beneath the greenhouse with a height of 2m and the boundaries are well-insulated via vacuum insulation panels to provide adiabatic conditions yielding to no heat loss from the edges. Through electric heaters placed inside the target mass of soil, thermal energy is stored inside the soil via the power coming from photovoltaic (PV) panels fixed on the roof of the greenhouse. A specific thin film PV glazing technology called heat insulation solar glass (HISG) is preferred for the power input to the greenhouse. As the first aim of the research, heating demand of the greenhouse is determined for each month. Temperature difference and overall heat transfer coefficient between indoor and outdoor environment are considered to be independent variables in the analyses. Secondly, soil-based thermal energy storage system is introduced and its potential contribution to the heating demand is discussed. The preliminary results indicate that the soil mass is a dominant parameter in soil temperature and hence the thermal energy storage capacity. For a soil mass of 250 tonne, around 600K soil temperature is achieved by the end of year, which is very remarkable

Thermal and Acoustic Properties of Aerogels: Preliminary Investigation of the Influence of Granule Size

8th International Conference on Sustainability in Energy and Buildings, SEB 2016 The influence of granules size in silica aerogels is experimentally investigated in terms of thermal and acoustic performance characteristics. The transmission loss (TL) is measured at normal incidence in a traditional impedance tube, whereas the thermal conductivity (?) is evaluated using a Hot Plate apparatus, setting up an appropriate methodology, due to the nature of the sample. The results reveal that the small granules (granules size in the 0.01-1.2 mm range), which have the highest density, have the best performance both in terms of thermal and acoustic properties. Depending on the granules size, ? varies in 19-22 mW/mK range at 10°C, whereas a TL equal to 13 dB at about 6400 Hz for 20 mm thickness is obtained for small granules. © 2017 The Authors

Floating PVs in Terms of Power Generation, Environmental Aspects, Market Potential, and Challenges

This is the final version. Available on open access from MDPI via the DOI in this recordLimited reserves of fossil fuels, rising environmental concerns, and a remarkable increase in electricity demand have led to the necessity of harnessing solar energy on a large scale. For this purpose, there has been a noticeable stimulation into photovoltaic power plants (PVPPs) over the last three decades, but the land requirement for PVPPs is still a handicap in many countries since valuable lands are considered for other purposes such as agriculture and livestock. For effective conservation of valuable lands and water resources, PVPPs are preferred to be installed on various water bodies such as oceans, seas, lagoons, lakes, rivers, dams, canals, wastewater treatment plants, irrigation ponds, fish farms, wineries, reservoirs, etc. PV systems on water bodies are called floating PVPPs, and they have outstanding advantages compared with land-based PVPPs including better energy generation owing to passive cooling effects, higher system efficiency and reliability, and lower dirt and dust accumulation on PV modules thus lower operating costs. There are also some significant environmental features provided by floating PVs. Shading effects due to PV coverage reduce water losses arising from evaporation. Moreover, algae growth is limited because of mitigated solar radiation, which yields better water quality. This review presents more insight on floating PVPPs in terms of several aspects such as electricity generation, system efficiency, reliability and sustainability, experimental applications and facilities in operation, water and carbon saving as well as challenges

Recent passive technologies of greenhouse systems: a review

There are 130 countries produces greenhouse vegetables commercially with more than 1.1 million acres in 2016. Most of the greenhouses deal with high operating costs due to the great energy needs. The high heat loss because of the greenhouse envelope material is responsible for the high energy demand in greenhouses. Nevertheless, each area having a specific need which affects to the energy level and conventional greenhouse technologies tend to have poor U-values. It causes energy for heating is very dominant up to 85% of the total greenhouse energy demand in cold climates countries. While, for the hot climate countries the energy for cooling is more prevalent. Therefore, this paper presents the latest technological developments used in greenhouses in various countries used to control the microclimate in the greenhouse focusing on passive techniques. It is found that PCM recently used to provide heating and cooling for Mediterranean climate. Moreover, closed greenhouse concept based system for Northern climatic improves the reduction energy demands by 80% with a potential payback of 6 years. Additionally, for most countries double glazing envelopes to be the most frequently powerful to increase the greenhouse performance