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In new and refurbished buildings, different energy sources are usually exploited to reach the Near Zero Energy Building target. Heat pumps and renewables are the most common adopted technologies. The coupling of the different components with a control logic conceived to exploit all energy contributions causes an implied design complexity. In this paper, two case studies were reported regarding the use of multisource heat pump systems: as main novelties, the correct design of the solar field (thermal or photovoltaic/thermal) in relation with the other sources (ground heat exchangers, ventilation heat recovery) for a given building and climate was reported in order to balance the energy drawn and injected into the ground around the year, and to attempt to reach the independency from the electric grid. Moreover, the relatively complex (compared to conventional heating or cooling) system controlling for multisource heat pump plants was simulated. The paper reported on the design of the plant, of the control logic, and the energy performance of two original multisource heat pump systems by means of dynamic simulation. In one case, real measured data were available as well. Very high primary energy ratios were obtained due to suitable control logics of the multisource plants, around 1.4 (based on measured data) and 4.7 (based on simulated data) for the first and second case, respectively. As a consequence, non-renewable primary energy consumptions of 37 and 3.9 kWh m−2 y−1 were determined, respectively.
Filippo Busato; Renato Lazzarin; Marco Noro. The Control of Renewable Energies to Improve the Performance of Multisource Heat Pump Systems: A Two-Case Study. Applied Sciences 2021, 11, 6653 .
AMA StyleFilippo Busato, Renato Lazzarin, Marco Noro. The Control of Renewable Energies to Improve the Performance of Multisource Heat Pump Systems: A Two-Case Study. Applied Sciences. 2021; 11 (14):6653.
Chicago/Turabian StyleFilippo Busato; Renato Lazzarin; Marco Noro. 2021. "The Control of Renewable Energies to Improve the Performance of Multisource Heat Pump Systems: A Two-Case Study." Applied Sciences 11, no. 14: 6653.
Until recently, solar assisted heat pumps have used solar collectors as a cold source. Solar collectors provide, when possible, direct heat, otherwise they offer temperature levels to the heat pump evaporator higher than the outside air. At the same time, solar thermal cooling exploits the solar collectors and the absorption chiller only in hot months. Photovoltaic/Thermal (PVT) modules have been available on the market in recent years for solar cogeneration, but their utilization can be problematic due to PhotoVoltaic (PV) cell damage in cases where there is no heating request. This paper considers the possibility of coupling evacuated tube collectors and photovoltaic/thermal modules to drive an absorption heat pump-based plant operating as an absorption chiller in the summertime. The cold source is the solar energy and the ground, which is recharged by the solar thermal and photovoltaic/thermal collectors and by the cooling of the absorber-condenser in mid-seasons and summer. This study analyzes the system behavior in yearly operation and evaluates the role of suitable storage tanks in two different climates, varying the size of the two solar fields and the generator tank. In the best plant configuration, a primary energy ratio of 26.6 in colder climates with cloudy skies and 20 in hotter climates with clearer skies is obtained.
Marco Noro; Renato Lazzarin. PVT and ETC Coupling for Annual Heating and Cooling by Absorption Heat Pumps. Sustainability 2020, 12, 7042 .
AMA StyleMarco Noro, Renato Lazzarin. PVT and ETC Coupling for Annual Heating and Cooling by Absorption Heat Pumps. Sustainability. 2020; 12 (17):7042.
Chicago/Turabian StyleMarco Noro; Renato Lazzarin. 2020. "PVT and ETC Coupling for Annual Heating and Cooling by Absorption Heat Pumps." Sustainability 12, no. 17: 7042.
A large fraction of the energy demand is due to space heating. Direct solar heating might reduce the need of fossil fuels. However the poor solar collector efficiency when outside temperature and solar radiation are low, as in the heating season, limit most of solar collectors application to domestic hot water heating. Similarly air source heat pumps are penalized just when the heating demand is higher. Then a possible solar contribution to the outside air as a heat pump cold source was first analyzed, evaluating different integration modes of the two sources. Subsequently the coupling of a ground source and a solar section appeared a more favourable application, also because solar heat could recharge the ground in periods of low or no heating demand. At the same time the solar section might reduce the length of the expensive boreholes. Solar assisted absorption heat pumps were successfully experimented. Recently studies were devoted to a solar assistance of heat pumps by PV/T collectors, that offer both a fraction of the electricity to drive the heat pump and a solar assistance to the heat pump cold source, be it the ground or the outside air.
R. Lazzarin. Heat pumps and solar energy: A review with some insights in the future. International Journal of Refrigeration 2020, 116, 146 -160.
AMA StyleR. Lazzarin. Heat pumps and solar energy: A review with some insights in the future. International Journal of Refrigeration. 2020; 116 ():146-160.
Chicago/Turabian StyleR. Lazzarin. 2020. "Heat pumps and solar energy: A review with some insights in the future." International Journal of Refrigeration 116, no. : 146-160.
Dual or multisource heat pumps were conceived to obviate to the defects of a single source, such as outside air, ground, water or solar radiation. Concerning the latter, the use of Photovoltaic/Thermal (PV/T or PVT) modules allows not only to partially recover the otherwise lost heat, but also to cool the PV and increase its electrical efficiency. Many studies simulated the possible behavior of combination of PVT with other sources, but generally unglazed PVT collectors were used. Only few results based on coupling glazed PVT to ground source heat pumps are available in literature. The use of glazed PVT increases thermal efficiency of the collector, and the coupling of ground allows to keep the electrical efficiency at high values without the risk of cells damage due to overheating. A refurbished building located in Northern Italy will be equipped by a PVT dual source heat pump, operating with the ground as source/sink, whereas the PVT drives the heat pump compressor and acts as a dual source. When the heat pump does not need heat or operates for summer air conditioning, the ground is the heat sink both for the heat pump and for the PVT cooling. A dynamic simulation allowed to size the plant and set up a suitable control logic of the main equipment. Very high efficiency and low primary energy consumption are demonstrated for the whole plant, thanks also to the high energy independency from the grid.
Renato Lazzarin; Marco Noro. Photovoltaic/Thermal (PV/T)/ground dual source heat pump: Optimum energy and economic sizing based on performance analysis. Energy and Buildings 2020, 211, 109800 .
AMA StyleRenato Lazzarin, Marco Noro. Photovoltaic/Thermal (PV/T)/ground dual source heat pump: Optimum energy and economic sizing based on performance analysis. Energy and Buildings. 2020; 211 ():109800.
Chicago/Turabian StyleRenato Lazzarin; Marco Noro. 2020. "Photovoltaic/Thermal (PV/T)/ground dual source heat pump: Optimum energy and economic sizing based on performance analysis." Energy and Buildings 211, no. : 109800.
It is well-known that the use of the latent heat absorption phenomenon associated with the melting process of a suitable Phase Change Material (PCM) can be considered an effective way to improve energy storage capabilities in many applications. This work experimentally investigates the effects of six open-cell aluminum foams and of a 3-D periodic aluminum structure during the phase change process of a paraffin wax with melting temperatures of 40°C in a hybrid water thermal storage unit. The storage is set at two different temperatures (50°C and 60°C) during the melting process, and at around 23°C during the solidification one. Moreover, in order to simulate the possible advantages of hybrid water thermal energy storages, a Trnsys Type developed to simulate the loading (melting) and unloading (solidification) processes of paraffin waxes for latent thermal energy storages is presented and validated against the data collected during experimental tests.
Giulia Righetti; Renato Lazzarin; Marco Noro; Simone Mancin. Phase change materials embedded in porous matrices for hybrid thermal energy storages: Experimental results and modeling. International Journal of Refrigeration 2019, 106, 266 -277.
AMA StyleGiulia Righetti, Renato Lazzarin, Marco Noro, Simone Mancin. Phase change materials embedded in porous matrices for hybrid thermal energy storages: Experimental results and modeling. International Journal of Refrigeration. 2019; 106 ():266-277.
Chicago/Turabian StyleGiulia Righetti; Renato Lazzarin; Marco Noro; Simone Mancin. 2019. "Phase change materials embedded in porous matrices for hybrid thermal energy storages: Experimental results and modeling." International Journal of Refrigeration 106, no. : 266-277.
The use of phase change materials (PCM) can be considered an effective way to improve the energy storage capabilities of hybrid water thermal energy storage (TESs) in solar heating and cooling plants. However, due to a few shortcomings, their use is still limited. This paper aims to give a direct estimation of the considerable advantages achievable by means of these hybrid TESs by simulating the annual performance of an existing gymnasium building located in northern Italy. The solar heating/cooling and ground source absorption heat pump plant is simulated using Trnsys. A validated type allows for the simulation of the hybrid water TESs, and also includes the possibility to use aluminum foams to enhance the heat transfer capabilities of the paraffin waxes used as PCM. This paper presents an optimization of the plant design from both energy and economic points of view by considering different cases: all three tanks modeled as sensible (water) storage, or one of the tanks modeled as PCM storage, or as enhanced PCM with metal foam.
Renato Lazzarin; Marco Noro; Giulia Righetti; Simone Mancin. Application of Hybrid PCM Thermal Energy Storages with and without Al Foams in Solar Heating/Cooling and Ground Source Absorption Heat Pump Plant: An Energy and Economic Analysis. Applied Sciences 2019, 9, 1007 .
AMA StyleRenato Lazzarin, Marco Noro, Giulia Righetti, Simone Mancin. Application of Hybrid PCM Thermal Energy Storages with and without Al Foams in Solar Heating/Cooling and Ground Source Absorption Heat Pump Plant: An Energy and Economic Analysis. Applied Sciences. 2019; 9 (5):1007.
Chicago/Turabian StyleRenato Lazzarin; Marco Noro; Giulia Righetti; Simone Mancin. 2019. "Application of Hybrid PCM Thermal Energy Storages with and without Al Foams in Solar Heating/Cooling and Ground Source Absorption Heat Pump Plant: An Energy and Economic Analysis." Applied Sciences 9, no. 5: 1007.
Renato M Lazzarin; Simone Mancin; Marco Noro; Giulia Righetti. Hybrid PCM—aluminium foams’ thermal storages: an experimental study. International Journal of Low-Carbon Technologies 2018, 13, 286 -291.
AMA StyleRenato M Lazzarin, Simone Mancin, Marco Noro, Giulia Righetti. Hybrid PCM—aluminium foams’ thermal storages: an experimental study. International Journal of Low-Carbon Technologies. 2018; 13 (3):286-291.
Chicago/Turabian StyleRenato M Lazzarin; Simone Mancin; Marco Noro; Giulia Righetti. 2018. "Hybrid PCM—aluminium foams’ thermal storages: an experimental study." International Journal of Low-Carbon Technologies 13, no. 3: 286-291.
Dual or multisource heat pumps were conceived to obviate to the defects of a single source, outside air or ground or solar radiation. Many studies simulated the possible behavior of combination of sources, but only few experimental results based on long term surveys on operating buildings are available in literature. A long term survey on a multisource heat pump system for the heating of a school building located in northern Italy gives the possibility of an evaluation based on real data. The main design features of the building incorporate a well insulated envelope, and a space heating and ventilation system driven by an innovative multisource heat pumps system. The latter incorporates outdoor air, ground, solar radiation, and heat recovery as heat sources, so enhancing the performance in terms of heating capacity and overall efficiency. The surveyed period concerns the last five heating seasons (2012-2017) allowing an assessment of the energy performance of the system based on real data monitored. The analysis permitted to identify incorrect settings, bad operation of the plant and heat pumps underutilization. The heating service was all the same assured, and the natural gas demand, almost steady if not in slight decrease, did not worry the management. Only the availability of data records and a careful analysis allowed to identify the bad working of the plant and the failure to achieve potential energy savings. The main novelty of this work is the highlighting of the paramount importance of monitoring and carefully analyzing recorded data as a guide to the plant management to keep correct operations, particularly when the plant integrates many different technologies even in the long term.
Renato Lazzarin; Marco Noro. Lessons learned from long term monitoring of a multisource heat pump system. Energy and Buildings 2018, 174, 335 -346.
AMA StyleRenato Lazzarin, Marco Noro. Lessons learned from long term monitoring of a multisource heat pump system. Energy and Buildings. 2018; 174 ():335-346.
Chicago/Turabian StyleRenato Lazzarin; Marco Noro. 2018. "Lessons learned from long term monitoring of a multisource heat pump system." Energy and Buildings 174, no. : 335-346.
PhotoVoltaic/Thermal cogeneration (PV/T) aims to utilize the same area both for producing electricity and heat. An electric compression heat pump can be coupled to the PV/T panels to contribute to the space heating demand partially using the self-produced electricity. Some Italian climates and economic incentives scenarios are considered with Trnsys simulations to evaluate the energy and economic viability of PV/T-heat pump hybrid technology. Primary energy saving results to be between 35% and 65%, and discounted payback of the investment can be around 10 years in mild climates and southern resorts.
Marco Noro; Renato M Lazzarin. Hybrid PhotoVoltaic–Thermal heat pump systems: energy and economic performance evaluations in different climates. International Journal of Low-Carbon Technologies 2017, 13, 76 -83.
AMA StyleMarco Noro, Renato M Lazzarin. Hybrid PhotoVoltaic–Thermal heat pump systems: energy and economic performance evaluations in different climates. International Journal of Low-Carbon Technologies. 2017; 13 (1):76-83.
Chicago/Turabian StyleMarco Noro; Renato M Lazzarin. 2017. "Hybrid PhotoVoltaic–Thermal heat pump systems: energy and economic performance evaluations in different climates." International Journal of Low-Carbon Technologies 13, no. 1: 76-83.
Many renwable energy plants are put into operation without providing a monitoring system to evaluate their performance over time. Then if is often difficult to realise the bad working of the system and the loss of efficiency results in an economic loss. Three quite different examples are reported to illustrate how real performance can be lower than designed due respectively: 1. To bad settings of the parameters; 2. To a hurried commissioning that did not reveal the mistakes in the design of the plant; 3. To a failure of a single component over time.
Renato Lazzarin. The importance of monitoring renewable energy plants: three case histories. E3S Web of Conferences 2017, 22, 100 .
AMA StyleRenato Lazzarin. The importance of monitoring renewable energy plants: three case histories. E3S Web of Conferences. 2017; 22 ():100.
Chicago/Turabian StyleRenato Lazzarin. 2017. "The importance of monitoring renewable energy plants: three case histories." E3S Web of Conferences 22, no. : 100.
Marco Noro; Renato M. Lazzarin; Andrea D’Ascanio. Energy and economic analysis of an under-ground water source heat pump system for a historical valuable building. Energy Procedia 2017, 133, 171 -182.
AMA StyleMarco Noro, Renato M. Lazzarin, Andrea D’Ascanio. Energy and economic analysis of an under-ground water source heat pump system for a historical valuable building. Energy Procedia. 2017; 133 ():171-182.
Chicago/Turabian StyleMarco Noro; Renato M. Lazzarin; Andrea D’Ascanio. 2017. "Energy and economic analysis of an under-ground water source heat pump system for a historical valuable building." Energy Procedia 133, no. : 171-182.
Though in a foundry most of the energy is used in the process plants and particularly in energizing furnaces, service plants require absolutely large amounts of energy, above all as electricity. The most energy-consuming service is compressed air preparation, but large amounts are due to lighting, heating, ventilation and air conditioning, pumps and fans. These energy users are common to most of the industrial branches with different weights both in absolute and relative terms. This article reports on the experience of some energy audits carried out in five Italian cast iron foundries allowing to identify the relative importance of different services in this industrial branch. The analysis is based on real data measured during the audits. Energy saving actions were then conceived, comparing the results of new technologies applied in some factory sectors and the energy usage of the previous equipment.
Renato M. Lazzarin; Marco Noro. Energy efficiency opportunities in the service plants of cast iron foundries in Italy. International Journal of Low-Carbon Technologies 2016, 1 .
AMA StyleRenato M. Lazzarin, Marco Noro. Energy efficiency opportunities in the service plants of cast iron foundries in Italy. International Journal of Low-Carbon Technologies. 2016; ():1.
Chicago/Turabian StyleRenato M. Lazzarin; Marco Noro. 2016. "Energy efficiency opportunities in the service plants of cast iron foundries in Italy." International Journal of Low-Carbon Technologies , no. : 1.
Foundry sector is one of the most energy intensive in industry. Energy audits performed in 5 Italian cast\ud iron foundries allowed to identify energy utilization in the various processes that from the melting of the\ud iron arrive at the finishing of the casting. Main equipment was surveyed, evaluating the influence on the\ud overall energy consumption, producing a detailed analysis of energy use per department and energy\ud performance indexes.\ud A separate study was carried out for foundries with induction furnaces and cold or hot blast cupolas.\ud Possibilities of heat recovery was identified particularly in combustion air preheating, but also for\ud building heating or to power direct cycles to produce electricity. Better insulation and new insulating\ud materials can improve the efficiency and the quality of the processes. Suggestions are supplied in the\ud various foundry departments for energy saving.\ud Possible energy saving actions on the service plants will be dealt with in a separate paper
Renato M. Lazzarin; Marco Noro. Energy efficiency opportunities in the production process of cast iron foundries: An experience in Italy. Applied Thermal Engineering 2015, 90, 509 -520.
AMA StyleRenato M. Lazzarin, Marco Noro. Energy efficiency opportunities in the production process of cast iron foundries: An experience in Italy. Applied Thermal Engineering. 2015; 90 ():509-520.
Chicago/Turabian StyleRenato M. Lazzarin; Marco Noro. 2015. "Energy efficiency opportunities in the production process of cast iron foundries: An experience in Italy." Applied Thermal Engineering 90, no. : 509-520.
Marco Noro; Filippo Busato; Renato M. Lazzarin. UHI effect in the city of Padua: Simulations and mitigation strategies using the Rayman and Envimet models. Geographia Polonica 2014, 87, 517 -530.
AMA StyleMarco Noro, Filippo Busato, Renato M. Lazzarin. UHI effect in the city of Padua: Simulations and mitigation strategies using the Rayman and Envimet models. Geographia Polonica. 2014; 87 (4):517-530.
Chicago/Turabian StyleMarco Noro; Filippo Busato; Renato M. Lazzarin. 2014. "UHI effect in the city of Padua: Simulations and mitigation strategies using the Rayman and Envimet models." Geographia Polonica 87, no. 4: 517-530.
Steel industry presents one of the highest energy demand of all the industrial sector. Foundries have a really relevant role both in economical terms and as regards the energy demand. The cost of energy represents several percentage points of the overall costs of a foundry. The electricity demand is very high, particularly for the induction melting furnaces. A large amount of thermal energy is obtained both from natural gas combustion and from the coal needed for the process of formation of cast iron in cupolas. Moreover, the plant services must be considered: one very energy consumer is compressed air production. Every factory is different from another so that the proposal of actions of energy savings or thermal recovers requires a detailed study of each plant considering the lay out and analysing the single processes with related energy needs and thermal levels. The co-operation of the University of Padua with the Centro Produttivita` Veneto allowed to plan a series of energy audits in some foundries located in Vicenza province. The experiences of the first facilities surveys and audits recommendations demonstrated both potential advantage of energy savings and the related difficulties, often due to the high investment costs.\ud Anyhow the joint work of auditing between the university experts and the foundry technicians produced a better awareness on the critical points of the plant and a higher rationality level in the evaluation of investments for the renewable of the machinery. Here, the method of performing the energy audits is described together with the very first results in terms of roposals for energy savings evaluated technically and economically
Massimo G Noro; Renato M Lazzarin. Energy audit experiences in foundries. International Journal of Energy and Environmental Engineering 2014, 7, 409 -423.
AMA StyleMassimo G Noro, Renato M Lazzarin. Energy audit experiences in foundries. International Journal of Energy and Environmental Engineering. 2014; 7 (4):409-423.
Chicago/Turabian StyleMassimo G Noro; Renato M Lazzarin. 2014. "Energy audit experiences in foundries." International Journal of Energy and Environmental Engineering 7, no. 4: 409-423.
The Urban Heat Island effect concerns the higher air temperature in urban environment with respect to the rural one. This phenomenon is well known by hundreds of years, but it has been experimentally studied only in the last few decades and in large metropolis. Very different possibilities concerning the measurements are possible (fixed ground based meteorological stations, “transept” measurements, satellite-based infrared sensors), with different difficult and quality of the data measured. The paper reports on the experimental results obtained by a research group of the University of Padua (Italy) in 2010 and 2011 springs-summers in Padua city. The main thermo-hygrometric variables (dry-bulb temperature, relative humidity, global solar radiation) have been measured along some different paths fixed in advance. The paths have been selected in order to cross different zones of the fabric of the city: urban, sub-urban and rural. The high number of “transepts” implemented in different time bands during the day and after the sunset allows to characterize the phenomenon in different meteorological conditions. The results indicate a presence of the UHI in urban zones of the city up to 5 °C. This work is intended to be developed during 2012 by the research group of the Department of Management and Engineering of the University of Padua, in cooperation with Co.Ri.La. (Venice) in the European Project “UHI – Development and application of mitigation and adaptation strategies and measures for counteracting the global Urban Heat Islands phenomenon” (3CE292P3). The paper reports the analysis of data recorded by two fixed meteorological stations (in the centre and out of Padua) during the period 1994–2011, that show some increase in the UHI effect during this period. Some guidelines concerning the choice of the experimental measurements settings are supplied by the Authors. The future measurements will be used also to calculate some outdoor comfort index and to verify how the latter will change modifying some characteristic parameters (buildings placement, thermal properties, trees presence, etc.) by a simulation model.
Marco Noro; Renato Lazzarin; Filippo Busato. A First Experimental Survey on the Urban Heat Island in Padua (Italy). Progress in Sustainable Energy Technologies: Generating Renewable Energy 2014, 683 -698.
AMA StyleMarco Noro, Renato Lazzarin, Filippo Busato. A First Experimental Survey on the Urban Heat Island in Padua (Italy). Progress in Sustainable Energy Technologies: Generating Renewable Energy. 2014; ():683-698.
Chicago/Turabian StyleMarco Noro; Renato Lazzarin; Filippo Busato. 2014. "A First Experimental Survey on the Urban Heat Island in Padua (Italy)." Progress in Sustainable Energy Technologies: Generating Renewable Energy , no. : 683-698.
The concept of a low energy building in the temperate climate (according to the Koppen climate classification) is based on the reduction of heat losses through a better insulation, the heat recovery on mechanical ventilation and the use of high efficiency heating/cooling systems integrated with renewables. It is very difficult to achieve good results in terms of global energy efficiency if one of these elements is missing. In 2009 a new school building, integrating those three elements, started its operation in Agordo town, northern Italy. Its main features concern a well insulated envelope and a space heating and ventilation system driven by an innovative multisource heat pump system concept. Outdoor air is a common heat source, whose limits are well known. Heat pump features can take advantage of better sources than air, as for instance the ground heat, solar heat, and heat recovery. These sources are those used by the analyzed system. A multisource system aims to enhance the performances of the heat pump, both in terms of heating capacity and of efficiency, of the heat pump. The present work shows data monitoring and analysis for a real working application, for a period of about two heating seasons, during which the behavior of the system can be analysed and the eventual malfunctioning of the plant can be identified. The energy balance indicates that the integration of different sources not only increases the thermal performance of the system as a whole but also optimizes the use of each source, thus leading to a lower stress on the ground and to a higher utilization of the solar system. The results are then compared to those could have been obtained with the use of a single source system, i.e. the ground, taking no advantage from the heat recovery and the solar system.
Marco Noro; Renato Lazzarin; Filippo Busato. Multisource Heat Pump System: The Case Study of a New School Building. Progress in Sustainable Energy Technologies Vol II 2014, 591 -607.
AMA StyleMarco Noro, Renato Lazzarin, Filippo Busato. Multisource Heat Pump System: The Case Study of a New School Building. Progress in Sustainable Energy Technologies Vol II. 2014; ():591-607.
Chicago/Turabian StyleMarco Noro; Renato Lazzarin; Filippo Busato. 2014. "Multisource Heat Pump System: The Case Study of a New School Building." Progress in Sustainable Energy Technologies Vol II , no. : 591-607.
This paper considers different cooling systems and investigates the most promising alternatives when solar energy is to be used to supply the cooling demand. All the systems are evaluated during a summer cooling season by the energetic and economic point of view by dynamic simulation for two different climates. For Milan (Cfb climate) the highest OSE (overall system efficiency) is reached by LiBr (lithiumbromide) double effect absorption chiller driven by parabolic through collector (0.53). In terms of the collecting surface area, the best systems for Milan feature 0.08 m2 MJ1 per day both for electric system (mono-crystalline photovoltaic coupled to water cooled chiller) and thermal system (PTC (parabolic trough collectors) coupled to double effect water-LiBr absorption chiller). Southern latitudes like Trapani (Csa climate) allow a quite better performance for thermal solar cooling solutions. The NPV (net present worths) of electric solar cooling solutions are favorable with respect to the traditional solution and the DPV (discounted payback periods) are all lower than the period of economic analysis above all for water cooled chillers. Finally a sensitivity analysis of the specific investment cost (V MJ1 per day) is carried out regarding the investment cost of collectors, the solar ratio and the interest rate
M. Noro; R.M. Lazzarin. Solar cooling between thermal and photovoltaic: An energy and economic comparative study in the Mediterranean conditions. Energy 2014, 73, 453 -464.
AMA StyleM. Noro, R.M. Lazzarin. Solar cooling between thermal and photovoltaic: An energy and economic comparative study in the Mediterranean conditions. Energy. 2014; 73 ():453-464.
Chicago/Turabian StyleM. Noro; R.M. Lazzarin. 2014. "Solar cooling between thermal and photovoltaic: An energy and economic comparative study in the Mediterranean conditions." Energy 73, no. : 453-464.
Many technologies are available to produce solar cooling. The most widespread options are solar thermal driven sorption and photovoltaic driven compression chillers. Sorption chillers can be single or double effect LiBr–H2O water cooled or H2O–NH3 air cooled. The requested temperatures are respectively around 90 °C for the first engine and 160 °C for the other two. The solar section can be realised with flat plate or evacuated tube collectors at a fixed tilt or parabolic trough collectors with a tracking system. The possible solar cooling systems are evaluated during a sunny day and compared with the PV driven system first with respect to the overall system efficiency. Finally the comparison regards also the investment cost for the various systems. Whereas in the past the PV driven system was considered too expensive with respect to the solar thermal, now it is quite comparable above all if the systems are air cooled.
Renato M. Lazzarin. Solar cooling: PV or thermal? A thermodynamic and economical analysis. International Journal of Refrigeration 2014, 39, 38 -47.
AMA StyleRenato M. Lazzarin. Solar cooling: PV or thermal? A thermodynamic and economical analysis. International Journal of Refrigeration. 2014; 39 ():38-47.
Chicago/Turabian StyleRenato M. Lazzarin. 2014. "Solar cooling: PV or thermal? A thermodynamic and economical analysis." International Journal of Refrigeration 39, no. : 38-47.
Cycling losses may be defined as those inefficiencies that reduce the performances of units during the transient period. They may be quantified by comparing the Energy Efficiency Ratio (EER) of a cycling unit and the EER of the same unit working continuously. The on-off control is the most widespread strategy for modulating; therefore, a reliable evaluation of cycling losses is fundamental to assess the EER of the system. The mentioned losses have been experimentally evaluated on a test rig, and logged data demonstrate a loss up to 13% with respect to steady operations when the load factor is lower than 10% and a Thermostatic Expansion Valve (TEV) is used. The insertion of a solenoid valve in series with the TEV can reduce the losses but the best results are obtained by using the Electronic Expansion Valve (EEV) instead of the TEV
Giacomo Bagarella; Renato M. Lazzarin; Biagio Lamanna. Cycling losses in refrigeration equipment: An experimental evaluation. International Journal of Refrigeration 2013, 36, 2111 -2118.
AMA StyleGiacomo Bagarella, Renato M. Lazzarin, Biagio Lamanna. Cycling losses in refrigeration equipment: An experimental evaluation. International Journal of Refrigeration. 2013; 36 (8):2111-2118.
Chicago/Turabian StyleGiacomo Bagarella; Renato M. Lazzarin; Biagio Lamanna. 2013. "Cycling losses in refrigeration equipment: An experimental evaluation." International Journal of Refrigeration 36, no. 8: 2111-2118.