scholarly journals Analysis of a modular high efficiency Polygeneration System in a Science and Technological Park

Polygeneration systems refers to highly efficiency integrated systems characterized by the simultaneously production of different services (electricity, heating, cooling, water, etc) by means of several technologies using fossil and/or renewable energy sources. In many cases it is difficult to promote polygeneration projects due to its complexity. This complexity mainly comes from the high energy integration of the technologies involved in polygeneration plants and the high variability in the energy demand in many applications in the building sector that makes the design and optimal operation of these systems quite complex. The result is that without a very careful design and operation of these plants the economic viability is in many cases not clear. In this paper is presented an economic, energetic and environmental analysis of a polygeneration system in Cerdanyola del Vallès (Spain) built in the framework of the Polycity project of the European Concerto Program. This polygeneration system comprises three high efficient natural gas cogeneration engines with a total power capacity of about 10 MW with advanced thermal cooling facilities including a single effect hot water driven chiller and a double effect chiller of 5 MW driven directly by the exhaust gases of the engines. This plant provides electricity, heating and cooling to a new Science and Technological Park in development including a Synchrotron Light Facility through a district heating and cooling network with a total length of more than 30 km. The operational data for the energy performance analysis was taken using the plant SCADA system and a monitoring system specific for the cooling units in order to study in detail its performance. The results show that the polygeneration plant is an efficient way to reduce the primary energy consumption and CO2 emissions although it is not yet at its full capacity

2020 ◽  
Vol 29 (2) ◽  
pp. 223-233
Author(s):  
Ewa Figiel ◽  
Dorota Leciej-Pirczewska

New demands for lowering energy consumption of buildings lead to many new solutions including, amongst others, the introduction of an outer wall thermal barrier for both heating and cooling effect. The analysed thermo-active-wall-barrier is a water-based system, where the pipes are embedded in the wall construction. It enables the use of a low-temperature barrier medium for space heating, thereby increasing the efficiency of all potential energy supply systems using renewable energy sources. The pipes form an active thermal barrier for heat transfer between the outer and the heated space. There are many possibilities to place the pipes in the wall for example in the case of energetic thermo-modernisation. Our research and calculations have shown that thermo-active-wall-barrier is sensitive to the location of pipes. The following paper also provides a study of the impact of thermal barrier on a building’s energy performance. The analysis was conducted for a single-family house in a temperate climate based on parameters taken from one of the Polish meteorological data-bases. Calculations using current procedure of evaluating building energy performance show, that the thermal barrier can contribute to signifi cant reduction of transmission energy loss thus lowering the environmental impact.


Energies ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4603
Author(s):  
Francesca Ceglia ◽  
Adriano Macaluso ◽  
Elisa Marrasso ◽  
Carlo Roselli ◽  
Laura Vanoli

This paper presents a thermodynamic, economic, and environmental analysis of a renewable polygeneration system connected to a district heating and cooling network. The system, fed by geothermal energy, provides thermal energy for heating and cooling, and domestic hot water for a residential district located in the metropolitan city of Naples (South of Italy). The produced electricity is partly used for auxiliaries of the thermal district and partly sold to the power grid. A calibration control strategy was implemented by considering manufacturer data matching the appropriate operating temperature levels in each component. The cooling and thermal demands of the connected users were calculated using suitable building dynamic simulation models. An energy network dedicated to heating and cooling loads was designed and simulated by considering the variable ground temperature throughout the year, as well as the accurate heat transfer coefficients and pressure losses of the network pipes. The results were based on a 1-year dynamic simulation and were analyzed on a daily, monthly, and yearly basis. The performance was evaluated by means of the main economic and environmental aspects. Two parametric analyses were performed by varying geothermal well depth, to consider the uncertainty in the geofluid temperature as a function of the depth, and by varying the time of operation of the district heating and cooling network. Additionally, the economic analysis was performed by considering two different scenarios with and without feed-in tariffs. Based on the assumptions made, the system is economically feasible only if feed-in tariffs are considered: the minimum Simple Pay Back period is 7.00 years, corresponding to a Discounted Pay Back period of 8.84 years, and the maximum Net Present Value is 6.11 M€, corresponding to a Profit Index of 77.9% and a maximum Internal Rate of Return of 13.0%. The system allows avoiding exploitation of 27.2 GWh of primary energy yearly, corresponding to 5.49∙103 tons of CO2 avoided emissions. The increase of the time of the operation increases the economic profitability.


2014 ◽  
Vol 1020 ◽  
pp. 518-523
Author(s):  
Martin Kovac ◽  
Katarina Knizova

The subject of the paper is to calculate the energy performance of building in proposed variants. The differences in the variants are in the using of conventional and renewable sources for heating and domestic hot water system. Target of the second part of paper is to know, how much money we need to invest into the proposed variants for heating and domestic hot water systems and how much money will by the user paying for operating costs. The conclusion of the paper describes the payback periods of proposed variants.


2019 ◽  
Vol 3 (2) ◽  

In the recent attempts to stimulate alternative energy sources for heating and cooling of buildings, emphasise has been put on utilisation of the ambient energy from ground source heat pump systems (GSHPs) and other renewable energy sources. Exploitation of renewable energy sources and particularly ground heat in buildings can significantly contribute towards reducing dependency on fossil fuels. The study was carried out at the Energy Research Institute (ERI), between September 2016 and November 2017. This paper highlights the potential energy saving that could be achieved through use of ground energy source. The main concept of this technology is that it uses the lower temperature of the ground (approximately <32°C), which remains relatively stable throughout the year, to provide space heating, cooling and domestic hot water inside the building area. The purpose of this study, however, is to examine the means of reducing of energy consumption in buildings, identifying GSHPs as an environmental friendly technology able to provide efficient utilisation of energy in the buildings sector, promoting the use of GSHPs applications as an optimum means of heating and cooling, and presenting typical applications and recent advances of the DX GSHPs. It is concluded that the direct expansion of GSHP are extendable to more comprehensive applications combined with the ground heat exchanger in foundation piles and the seasonal thermal energy storage from solar thermal collectors. This study highlights the energy problem and the possible saving that can be achieved through the use of the GSHP systems. This article discusses the principle of the ground source energy, varieties of GSHPs, and various developments.


2019 ◽  
Vol 11 (4) ◽  
pp. 311-318
Author(s):  
A. V. Volkov ◽  
A. G. Parygin ◽  
A. A. Vikhlyantsev ◽  
A. A. Druzhinin

The conventional solution for HAPPs is the use of reversible hydraulic machines operating both in the pump mode as well as in the turbine mode. At the same time, for example, a blade system of a hydraulic machine designed for the pumping mode has a high efficiency. However, in the turbine mode, the energy characteristics of such machine are far from optimal. Considering different patterns of micro- and mini-HAPPs (up to 100 kW) of modular design, it is most appropriate to use a pump and a turbine separately, since the efficiency of hydraulic machines is very important in the case of such low power. To date, approaches to the design of hydraulic turbines are quite developed and allow to achieve high energy performance [1, 2]. According to different data sources the level of axial turbine efficiency with power less than 100 kW is about 80÷91%. At the same time, for centrifugal pumps, especially those of low specific speed, the problem of increasing energy efficiency is very urgent. E.g., for pumps with a specific speed ns< 80 the efficiency level is usually 40 to 65%. The aim of the presented research is the development of methods of synthesis and optimization of the flow passages of centrifugal pumps using the approaches of the theory of optimal control and increasing energy performance of hydraulic machines. Various ways of local correction of geometry of flow passages are presented in the paper. As an alternative to empirical approaches, methods based on the control of the circulation distribution are considered in detail. Various mathematical dependences of the flow circulation on the coordinate of the point lying on the surface of the blade are analyzed. Possibilities of application of the theory of experiment planning in relation to the problems to be solved are considered.


2020 ◽  
pp. 195-195
Author(s):  
Norbert Harmathy

The construction sector as one of the highest carbon emitters in the World has an international initiative for Green House Gas reduction. Green building certifications demonstrate performance, efficiency and economy in the constuction sector. The motivation of the research was to investigate whether Green certified buildings which fulfill the minimum energy standards do demonstrate high energy performance compared to energy efficient buildings and renewable systems. The hypothesis was to investigate that renewable energy source application could contribute to higher performance, against a typical efficient HVAC system (usually applied in commercial buildings) and a building aiming for Green certification, concerning mandatory energy efficiency requirement. The research scope was to investigate and evaluate various HVAC solutions using triple-criteria evaluation method for decarbonization: energy performance, carbon footprint and operation cost to formulate systematic solutions in the design phase of projects for wide audience with preferable and applicable results.


2021 ◽  
Vol 13 (24) ◽  
pp. 13934
Author(s):  
Hanan S. S. Ibrahim ◽  
Ahmed Z. Khan ◽  
Yehya Serag ◽  
Shady Attia

Retrofitting “nearly-zero energy” heritage buildings has always been controversial, due to the usual association of the “nearly-zero energy” target with high energy performance and the utilization of renewable energy sources in highly regarded cultural values of heritage buildings. This paper aims to evaluate the potential of turning heritage building stock into a “nearly-zero energy” in hot, dry climates, which has been addressed in only a few studies. Therefore, a four-phase integrated energy retrofitting methodology was proposed and applied to a sample of heritage residential building stock in Egypt along with microscale analysis on buildings. Three reference buildings were selected, representing the most dominant building typologies. The study combines field measurements and observations with energy simulations. In addition, simulation models were created and calibrated based on monitored data in the reference buildings. The results show that the application of hybrid passive and active non-energy generating scenarios significantly impacts energy use in the reference buildings, e.g., where 66.4% of annual electricity use can be saved. Moreover, the application of solar energy sources approximately covers the energy demand in the reference buildings, e.g., where an annual self-consumption of electricity up to 78% and surplus electricity up to 20.4% can be achieved by using photo-voltaic modules. Furthermore, annual natural gas of up to 66.8% can be saved by using two unglazed solar collectors. Lastly, achieving “nearly-zero energy” was possible for the presented case study area. The originality of this work lies in developing and applying an informed retrofitting (nearly-zero energy) guide to be used as a benchmark energy model for buildings that belong to an important historical era. The findings contribute to fill a gap in existing studies of integrating renewable energy sources to achieve “nearly-zero energy” in heritage buildings in hot climates.


Urban Science ◽  
2021 ◽  
Vol 5 (4) ◽  
pp. 82
Author(s):  
Maria Rosaria Guarini ◽  
Francesco Sica ◽  
Pierluigi Morano ◽  
Josè Antonio Vadalà

The International Energy Agency (2019) states 40% of CO2 emissions in cities are linked to the buildings stock, in particular to heating and cooling systems, material types and users’ performance. According to Green New Deal, the energy transition of buildings is becoming a priority. This is via investments with low environmental impacts through renewable energy sources. The paper describes an integrated economic-energy-environmental framework (IE3F), i.e., an economic evaluation protocol for new constructions and/or existing renewal projects aimed at supporting the choice phase between alternative technological solutions based on biocompatible materials. The IE3F borrows the logical-operative flow of the life cycle assessment multi-criteria approach. The value aspects translated into monetary terms that characterize the project life cycle are taken into account. The protocol was tested on an emergency project in Italy, namely in Messina City. The results obtained provide evidence of the versatile use of IE3F and its practical utility to guide economic convenience judgements on building investments and choice problems between alternatives in sustainable perspective. The research deepening will be about keeping track of multiple performance levels of the construction, not only the energy performance, and attempting to estimate the corresponding economic value in terms of increase/decrease of construction cost value.


Energies ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 1968 ◽  
Author(s):  
Marek Borowski ◽  
Piotr Mazur ◽  
Sławosz Kleszcz ◽  
Klaudia Zwolińska

The energy consumption of buildings is very important for both economic and environmental reasons. Newly built buildings are characterized by higher insulation and airtightness of the building envelope, and are additionally equipped with technologies that minimize energy consumption in order to meet legal requirements. In existing buildings, the modernization process should be properly planned, taking into account available technologies and implementation possibilities. Hotel buildings are characterized by a large variability of energy demand, both on a daily and a yearly basis. Monitoring systems, therefore, provide the necessary information needed for proper energy management in the building. This article presents an energy analysis of the Turówka hotel located in Wieliczka (southern Poland). The historical hotel facility is being modernized as part of the project to adapt the building to the requirements of a sustainable building. The modernization proposal includes a trigeneration system with a multifunctional reverse regenerator and control module using neural algorithms. The main purpose is to improve the energy efficiency of the building and adapt it to the requirements of low-energy buildings. The implementation of a monitoring system enables energy consumption to be reduced and improves the energy performance of the building, especially through using energy management systems and control modules. The proposed retrofit solution considers the high energy consumption, structure of the energy demand, and limits of retrofit intervention on façades.


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