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Solar Multi-Generation in the Mediterranean Area, the Experience of the Sts-Med Project

Authors:

Abstract

A solar multi-generation approach has been implemented through four demonstrative plants in Italy, Cyprus, Jordan and Egypt based upon solar concentrating collectors. Different design options have been developed, including technologies that have been adapted and downsized from the utility scale of CSP plants, with the aim to be integrated at building, settlement and community scale. Demo plants have been conceived as living labs in order to support the further development of the technologies in a real-life environment, supporting the local smart specialization strategies in collaboration with SMEs, local stakeholders and citizens.
Solar multi-generation in the Mediterranean area, the experience
of the STS-MED project
Alaric C. Montenon1, Filippo Paredes2, Alberto Giaconia3, N. Fylaktos1, Silvana Di Bono2,
Costas N. Papanicolas1 and Fabio Montagnino2
1 The Cyprus Institute, Aglantzia (Cyprus)
2 Consorzio ARCA, Palermo (Italy)
3 ENEA Casaccia Research Center, Rome (Italy)
Abstract
A solar multi-generation approach has been implemented through four demonstrative plants in Italy, Cyprus,
Jordan and Egypt based upon solar concentrating collectors. Different design options have been developed,
including technologies that have been adapted and downsized from the utility scale of CSP plants, with the
aim to be integrated at building, settlement and community scale. Demo plants have been conceived as living
labs in order to support the further development of the technologies in a real-life environment, supporting the
local smart specialization strategies in collaboration with SMEs, local stakeholders and citizens.
Keywords: multi-generation, solar thermal, CSP, storage, concentrating solar collectors, solar cooling,
building integration, smart specialization, living labs
1. Introduction
Global space cooling energy consumption increased by 60% between 2000 and 2010, reaching 4% of global
consumption (OECD/IEA Report 2013), meanwhile the production of heat accounts for more than 50% of
global final energy consumption (OECD/IEA Report 2014). The seasonal switch among the winter demand
of heat and the summer demand of cold is already a characteristic of the solar belt regions, including the
Mediterranean area. Therefore, specific efforts are needed in piloting innovative approaches to cover the
complex mix of heat, electricity, cold and other energy driven services by an optimized harvest, storage and
conversion of the solar radiation. As a matter of fact, seasonal demand can be holistically managed at a
settlement level by multi-generative solar concentration systems; the collection of high quality solar
radiation, mostly available in summer periods, can feed a solar cooling system in the hot days, while the
same collectors can cover the moderate heat demand in winter-time. Electricity can be generated from small
turbines or integrated PV panels. Residual heat can be used to drive other services, as the purification of
brackish, waste water or sea water desalination. Since November 2012, such a challenge is undertaken
through the Small scale Thermal Solar district units for Mediterranean communities (STS-Med) project,
supported by the ENPI- CBCMED program, with the construction of 4 pilot plants:
x in Palermo, Italy, led by Consorzio ARCA - coordinator of STS-Med - in the campus of the
University of Palermo, in partnership with the Italian National Agency for New Technologies,
Energy and Sustainable Economic Development (ENEA) for the Thermal Energy Storage (TES)
system,
x in Aglantzia, Cyprus, led by the Cyprus Institute (CyI), in the campus of the institute,
x in Markaz Belbes, Egypt, at Sekem Hospital, led by Academy of Scientific Research and
Technology (ASRT) and built by Elsewedy Electric,
x in Irbid, Jordan, led by Al Balqa Applied University (ALBUN) and built by Millennium Energy
Industries.
The 4 plants demonstrate that a smart integration and optimization of both commercially available and
innovative solar technologies can open a way towards the goal of zero energy communities in the
Mediterranean region (Rashad et al. 2015 and Kiwan et al. 2016).
© 2016. The Authors. Published by International Solar Energy Society
Selection and/or peer review under responsibility of Scientific Committee
doi:10.18086/eurosun.2016.05.06 Available at http://proceedings.ises.org
Figure 1. Novel Technologies Laboratory (left), rooftop of the University College in Irbid (right)
The buildings concerned self-produce the energy they need through sustainable systems, integrated at a
settlement level, with a significant reduction of CO2 emissions and consumption especially in seasonal peak.
The design of each demo site has been adapted accordingly with the result of specific energy audits and the
availability of either ground or roof space for the collectors. Local communities have been involved in
awareness activities and local SMEs have been invited to take part into educational activities during the
preparatory and erection phases.
In Italy, the collectors are installed in a field nearby the building and the plant is generating electricity by an
existing ORC (Organic Rankine Cycle) and heat/cold with the help of an absorption chiller integrated on the
HVAC system. The case-study in Cyprus is located in the premises of the Cyprus Institute in Aglanzia
(district of Nicosia), Cyprus. The objective of the plant is to support the heating, cooling and hot water
system of the Novel Technologies Laboratory (NTL, Figure 1, left) by reducing the use of the existing
electric heat-pumps. NTL was designed to be a near to zero energy building (Papanicolas 2015 et al.) by a
specific selection of the materials and orientation of the windows and walls, which minimize the energy
demand for air-conditioning. A 14.5 kW peak power photovoltaic generator covers a part of its electricity
consumption. In Jordan the collector is installed on the roof of one of the buildings at University College in
Irbid (Figure 1, right). As for the Cypriot plant, the system is installed on the roof a public building (Figure 2,
right). The objective of the plant is to provide heating and cooling to classrooms of the university and hot
water in case of over-production. A small steam turbine can be activated to generate electricity. The pilot
plant in Egypt is located in Belbes to support Sekem medical center HVAC, at 60 km from Cairo city center
as the crow flies. The collector is installed on plain field next to the hospital. A small ORC turbine is
generating electricity balancing the seasonal demand of cold.
2. Solar collectors
As shown in Figure 2 and Figure 3, solar fields in Cyprus, Egypt and Italy are based on North-South aligned
Linear Fresnel Collectors (LFC) or Linear Fresnel Reflectors (LFR). The installed LFRs, specifically
designed for integration in built environments, have been developed by Idea (Vasta 2013 et al.), an Italian
company affiliated to Consorzio ARCA. In Jordan the plant relies on a Parabolic Tough Collector (PTC,
Figure 3) manufactured by the Italian company Soltigua. The characteristics of the collectors are detailed in
Table 1. Platforms are located at different latitudes, from 30°25'05.5"N in Egypt to 38°06'01.0"N in Italy.
Figure 2. LFR at Palermo, Italy (left) and Nicosia, Cyprus (right)
Figure 3. PTC at Irbid, Jordan (left) and LFR at Egypt Markaz Belbes (right)
Table 1. Characteristics of the solar fields
Cyprus
Egypt
Italy
Jordan
Location
Aglantzia, on the
roof of a s
chool,
next to the NTL
Markaz Belbes,
nearby
the
Sekem
medical center
University of
Palermo, on the
ground at ARCA
Irbid, roof a
building of the
Balqa University
College
Latitude
Longitude
Elevation
(Above the
sea level)
35°08'28.1"N
33°22'50.7"E
176m
30°25'05.5"N
31°38'07.8"E
35m
38°06'01.0"N
13°20'37.3"E
50m
32°29'13.2"N
35°53'24.0"E
648m
Average DNI per year
(Source: SolarGis)
2142 kWh.m-2
1958 kWh.m-2
1703 kWh.m-2
2377 kWh.m-2
Type of collector
LFR - Idea
LFR - Idea
PTC - Soltigua
LFR
Global aperture area
184.32 m2
299.50 m2
483.84 m2
163.2 m2
Thermal oil, Heat
Transfer Fluid (HTF)
Duratherm 450
Therminol 66
Paratherm NF
Seriola eta 32 -
Total Lubmarine
Peak thermal power
70 kW
115 kW
190 kW
85 kW
Total
receiver length
32 m 52 m
84 m (3 x 28 m
receivers
rows)
38.56 m
Working temperatures
(outlet) 170°C 140°C 280°C 240°C
All the collectors are working with thermal oil as heat transfer fluid (HTF) at different temperature: from
140°C to 280°C. The total thermal peak power of the plants is 460kW. The platform in Palermo is the main
contributor with 190kW with 3 identical LFC parallel loops. Figure 4 shows a simplified layout of the solar
plant installed in Sicily.
Figure 4. Layout of the field at ARCA (Sicily)
Figure 5. DNI and thermal power on the 6th of September 2016 (Italy)
The thermal power and DNI on the 6th of September 2016 are shown in Figure 5. A peak of 160kW was
achieved at 12.30PM. In Cyprus 70kW peak power is installed. On the 26th of July 2016, the Fresnel
collector was commissioned. Thermal power and DNI are show in Figure 6. The output power reached 68.7
kW with a DNI of 800 W.m-2 at 12.52PM.
Figure 6. DNI and thermal power on the 26th of July 2016 (Cyprus)
The peak power installed in Egypt is 115kW and 85kW in Jordan. All the 4 for plants are equipped with a
vacuum receiver and with the association of a secondary reflector for the LFRs in Cyprus, Egypt and Italy
with estimated 90% optical efficiency. DNI is the highest in Jordan with 2377kWh.m-2 per year. DNI in
Cyprus is 2142kWh.m-2 per year and in Egypt 1958kWh.m-2 (Source: SolarGis Imaps, Beták et al. 2012).
DNI in Palermo is the lowest with 1703 kWh.m-2 per year. The solar fields were all completed in September
2016. Dimension of the mirrors of the 3 LFRs are identical: 0.32m x 2.000m. Cypriot LFR was the first to be
installed on the island (Montenon and Fylaktos 2016). It is composed of 288 mirrors with a reflective area of
184.32 m2, driven by 72 DC motors (4 mirrors per motor). In Egypt, the system is composed of 468 mirrors
and the reflective area is 299.52 m2, but driven by 13 DC motors (36 mirrors per motor). The Italian field is
hybrid: 2 LFC modules are configured as in Egypt and the third collector is configured according to the
Cypriot model. In this way it is possible to lead comparisons between the two strategies. On the one hand in
Cyprus the flexibility of the field is higher but requires more maintenance due to larger number of motors: if
one motor fails, the system will be only slightly impacted and can continuously operate with the rest of the
71 motors. On the other hand, the Egyptian collector relies on fewer motors, so requiring less maintenance,
but if one motor has to be changed a larger area of the solar field will be impacted; furthermore, tracking
angles of the motors is not independent and the whole field cannot be placed in flat position for cleaning
purpose for instance. In Cyprus and Italy, HTF loops are separated from the thermal storage medium.
Nonetheless, small buffers are installed in the HTF loops in order to stabilize the temperatures.
0
20
40
60
80
100
120
140
160
180
11 13 15 17 19
0
100
200
300
400
500
600
700
800
900
Thermal power (kW)
Time (hour)
DNI (W.m-2)
DNI Thermal power
0
10
20
30
40
50
60
70
80
9 101112131415
0
100
200
300
400
500
600
700
800
900
Thermal power (kW)
Time (hour)
DNI (W.m-2)
DNI Thermal power
Figure 7. HTF Loop at CyI (Cyprus) : oil loop (left) and pressurized vessel (right)
As shown on the main layout (Figure 4), in Sicily, on the field installed at ARCA a buffer tank is also
integrated in the HTF loop with a total volume of 800L containing 500L of thermal oil (Paratherm NF)
pressurized with nitrogen at 3bar (for a thermal storage capacity of 22kWh). In Cyprus the thermal oil
(Duratherm 450) is stored temporarily in an 800L tank (containing 425L of oil), pressurized with nitrogen at
3bar (Figure 7). A 3kW electric heater is wrapped around the tank to pre-heat the oil in case of cold start-up.
The role of these tanks is also to stabilize the outlet temperature of the piping. Pre-heating the oil decreases
the viscosity of the HTF and increases the Reynolds number to maintain it above 10,000 (turbulent flow).
Based on experience, the solar absorber pipe bends at low ranges of the Reynolds number, due to thermal
gradients, and it may get in contact and break the external glazing pipe. As soon as the oil inside the
buffering tanks is heated to a satisfactory value, the inverter pump of the HTF loop starts. The control of the
platforms in Cyprus and Italy aims to correlate the output with the real time value of the DNI. To that end,
two pyrheliometers are installed on the respective sites (Figure 8).
Figure 8. Pyrheliometers at ARCA (left) and the Cyprus Institute (right)
3. Thermal storage
Thermal storage is a key element of the four platforms. It permits to buffer the production for some minutes
to several hours. Details of the thermal storage in use in the 4 platforms are exposed in Table 2. In the plants
built in Jordan and Egypt, the HTF is directly stored respectively at 240°C and 140°C. In both Cyprus and
Italy, a heat-exchanger transfers the heat from the oil to TES system. In Cyprus thermal storage is based on
water pressurized with nitrogen up to 146°C ensuring 2 hours of autonomy for cooling in summer or 4 hours
for heating in winter. The same nitrogen tank is used to pressurize the thermal oil (Figure 9). Storage with
water is a low cost technology and vessels are available on Cypriot market.
Table 2. Thermal storages
Cyprus
Egypt
Italy
Jordan
Medium
Pressurized water
Thermal oil
(Therminol 66)
Ternary molten
salts mixture
Thermal oil
(
Seriola eta 32 -
Total Lubmarine)
Storage Volume
2.0 m3
2.8 m3
8 m3
1.3 m3
Storage capacity
100 kWh
21 kWh
400 kWh
30 kWh
Average temperature
146°C
140°C
260°C
240°C
Figure 9. Buffer of oil, expansion vessel, thermal storage tank (left to right) at CyI (left) and molten salts storage, oil storage
and expansion tank (left to right) at ARCA (right)
Safety relief-valves are installed on the tank in case of over-pressure. The developed TES integrated in the
pilot plant built in Sicily includes innovative features. Different options have been reviewed. TES systems
commonly applied in conventional CSP plants operate with “solar salts” (molten nitrates mixture
NaNO3/KNO3 60%/40% of weight distribution), in two-tanks heat storage system operating from 290°C
(cold tank) to 385°C (hot tank) when oils are used as HTF in the solar field (Lovegrove and Stein 2012). In
small CSP plants (lower than 1MW range) it is rather difficult to replicate such a complex scheme due to the
lower operative temperatures (280°C maximum in Sicily) and principally due to the need of expert personnel
to manage molten salts loops too. Therefore, an innovative TES system has been specifically developed in
STS-Med project. It is also based on molten salts, but the management of the TES is eased. This is lower
than the melting point “solar salts”, which is around 220°C (Serrano et al. 2013). Hence, the temperature
range is much more compatible with the above-mentioned small-medium CSP temperatures (up to 300°C).
Also the two-tanks configuration is replaced by a single-tank system avoiding any external pumping of the
molten salts and the critical management of pipelines against freezing. In the developed TES at ARCA, all
the typical operations of a CSP plant of charging and discharging are achieved inside the single buffer tank
where given temperature gradients and molten salts circulation are easily determined. Therefore, besides
lower equipment volume and cost reduction potentials, the plant operator does not have to manage molten
salts flows. Thus, the developed TES is tailored for residential users and fits into the STS-Med requirements.
The developed TES system is represented in Figure 10. The operation concept is based on the properties of
unmixed molten salts in the tank to thermally stratify along the vertical axis, as an effect of their low thermal
conductivity and the density variability with temperature. Two heat exchangers are immersed in the zones
where the temperature is lower (bottom) and higher (top) to be operated during the charging and discharging
phases. In a conventional two-tanks TES systems with the high temperature tank at TS-high = 385°C (and the
low temperature tank at TS-low = 290°C) about 280 m3 of “solar salts” shall be loaded to store 20 MWh
thermal energy, to drive a steam Rankine cycle.
Figure 10. Optimized TES system developed for STS-Med: general scheme with explanatory working conditions (left) and
prototype drawings (right)
The same principle can be applied to a smaller TES system with maximum temperature of 300°C, combined
with an Organic Rankine Cycle. In the pilot plant in Sicily, TES is filled up with about 7 m3 of eutectic
ternary salt mixture (42%/15%/43% of weight distribution). Considering the reduction of the overall amount
of salt, the use of a single tank instead of two tanks and the avoidance of external molten salt pumps and
pipelines, the cost (€/kWh thermal) of this optimized heat storage system developed can compete with the
large scale CSP benchmark.
In the framework of the STS-Med project a small TES prototype of 0.96 m3 has been designed, built,
installed and successfully tested at ENEA-Casaccia research center (Rome) in order to validate the concept
before the installation in the pilot plant in Sicily. Loading, mixing, and melting procedures of the salts in the
TES have been studied. The experimental results and concept validation with the prototype enhanced the
design of an up-scaled TES for the demonstration plant in Palermo. Specifically, further optimizations and
improvements have been performed in a “new” version of the TES installed in the STS-Med pilot plant in
Sicily. This upgraded prototype is designed to work in a thermal range of 160-280°C. It is characterized by
an inner volume around 8.0m3 (1.8m diameter, 4m height) corresponding to effective heat capacity of about
400kWh (thermal). The charging/discharging thermal power averages 250/125 kW (thermal). The tank has
been insulated with a 20cm coating of rock wool.
4. Cooling, heating and hot water
4.1. Cooling
Cooling is the central task of all the STS-Med platforms, due to climate considerations in the Mediterranean
areas concerned by the project. The 4 plants rely on absorption chillers (Figure 11) to provide chilled water
at 7°C. The global cooling capacity of the platforms averages 110.1kW. Chillers in Cyprus, Egypt and Italy
are LiBr (Lithium Bromide) based, while in Jordan it is ammonia based. In Cyprus, the model used is
YAZAKI WFC-SC10. It is water-fired at low temperature (88°C inlet, 83°C outlet). Its cooling capacity is
35kW with a COP (Coefficient of Performance) of 0.7.
Table 3. List of absorption chillers
Cyprus
Egypt
Italy
Jordan
Model
YAZAKI
WFC-SC10
YAZAKI
SH10
Broad
BCT 23
Robur
ACF 60-
00 HT
Type
LiBr Single
effect
LiBr Single
effect
LiBr Double
effect
Ammonia Single
effect
Firing medium
Water
Thermal oil
Thermal oil
Thermal oil
Cooling capacity
35 kW
35 kW
23 kW
17.1 kW
Inlet temperature
88°C
88°C
200°C
240°C
COP cooling
0.7
0.7
1
0.6
Heating capacity
48.3 kW
23 kW
Figure 11. Absorption chiller and cooling tower at CyI (left) and at ARCA (right)
The heat is transferred to the absorption chiller from the thermal storage medium through a heat-exchanger
(pressurized-water and water). Then the heat is stored in a 500L tank of water. This stabilizes the inlet
temperature for the chiller. A cooling tower dissipates the heat from the absorber and condenser chambers
(Figure 11). In Egypt the same capacity chiller is used but the heat medium is thermal oil instead of water. In
Italy, the double effect absorption chiller is the most performant with a COP of 1 and it includes its own
cooling tower (Figure 12). The cooling capacity is 23kW. The Jordanian chiller is a Robur HT model with a
cooling capacity of 17.1kW at COP 0.6. Its working temperature is 240°C.
4.2. Heating and hot water
The absorption chillers in Egypt and Italy are also heating in winter with better COP than cooling. Heating
capacity is 48.3 kW in Sekem and 23 kW in Palermo (Figure 11). In Cyprus the absorption chiller is simply
by-passed to heat directly two water stratified tanks (2000L each). The heat is supplied to the Air Handling
Units (AHU) and the Fan Coil Units (FCU) for the offices of the NTL. In Jordan, the absorption chiller is
also by-passed in winter. If the available solar energy exceeds the cooling and electricity generation
demands, the excess heat is released to hot water network through shell and tubular heat-exchanger. The
heated water is then stored in a tank. If the excess heat exceeds the storage capacity, it is dissipated by dry
cooling.
5. Electric power units
Platforms in Egypt and Italy (Figure 12) cogenerate with ORCs (Organic Rankine Cycles) fired with thermal
oil. They both have an electric capacity of 10 kW and gross efficiency of 10% (Table 4) and need a cooling
tower to dissipate the heat rejection. They produce electricity in parallel with heating or cooling. The ORC in
Egypt works with inlet temperatures of 125°C to 150°C. In Jordan the oil exchanges its heat with a steam
loop to operate a demonstrative steam turbine of 1.2kW of electric power (Figure 12).
Table 4. Power units in Egypt, Italy and Jordan
Egypt
Italy
Jordan
Element
ORC
ORC
Steam turbine
Electric power
10 kW
10 kW
1.2 kW
Medium
Thermal oil
Thermal oil
Steam
Figure 12. Steam turbine during the installation in Irbid (left) and ORC Rank turbine in Palermo with cooling tower (right)
6. Conclusions
Nowadays solar concentration platforms are designed to produce several thermal MW and generally for
electricity generation in desert places. STS-Med project demonstrated the possible application of solar
concentrating technologies within integrated multi-generative plants at small/middle scale in built
environment either on the ground (Egypt and Italy) either on roofs (Jordan and Cyprus). Production of heat
to directly drive absorption chillers through thermal energy storage permits to avoid the stage of
transformation to electricity. The residual heat can be used for electricity production with the help of ORCs.
Thus, the co-generation of heat and electricity reduces the global balance of the energy consumption of
buildings and not only the electric part. The thermal storage permits to shift the production at peak load with
good flexibility. In the plant built in Sicily an innovative thermal energy storage system based on the use of
molten salts and specifically tailored for small scale concentrating solar applications has been integrated. The
main limitation to downscale solar cooling is the lack of commercial small scale absorption chillers and
ORCs. At the same time COP of absorption chiller, even with double-effect, is still poor if compared to
electric heat-pumps. Efficiency of small ORC turbine is also poor and their application at the project scale
(5-10 kW) can be considered as demonstrative of larger (50-100kW) applications. In this scope, the 4 plants
have been conceived as living labs, introducing the technology mix into different real-life environments
acting as showcases for the respective local communities. Comparative studies of design options and
subsystems will permit to identify the best strategies for the overall optimization of both efficiency and cost;
at the same time the local academic and technical communities will have a joint and open access to the demo
facilities as platforms for future collaborations and developments.
7. Acknowledgments
The Small Scale Thermal Solar District Units for Mediterranean Communities (STS-MED) project was
financed by CrossBorder Cooperation initiative funded by the European Neighbourhood and Partnership
Instrument (ENPI). In its scope, the project aimed to raise 4 pilot solar plants for air-conditioning and
electricity generation in four different locations: Cyprus, Jordan, Egypt and Sicily. We would like to thank
the European Neighbourhood and Partnership Instrument, as well as the 14 partners in the project (Consorzio
ARCA, ENEA, Sicilian Region, CEEI, CEA, IASA, Egyptian new and Renewable energy ministry, ASRT,
Elsewedy Electric, Jordanian Ministry of Energy and Mineral Resources, ALBUN, Millenium Energy
Industries, Cyprus Chamber of Commerce and Industry and CyI).
8. References
Beták, J., Šúri, M., Cebecauer, T., Skoczek, A., Proc. 27th European Photovoltaic Solar Energy Conference
and Exhibition, Solar resource and photovoltaic electricity potential in EU Mena Region, Frankfurt,
Germany, 24-28 Sep., 2012, pp. 4623-6.
Kiwan, S., Damseh, R., Venezia, L., Montagnino, F.M., Paredes, F., Techno-Economic Performance
Analysis of a Concentrated Solar Polygeneration Plant in Jordan, GCREEDER 2016 at Amman, Jordan.
Lovegrove, K., Stein, W., Concentrating Solar Power Technology, 1st Edition, Principles, Developments and
Applications, Woodhead Publishing, pp 370, 19 October 2012
Montenon, A., Fylaktos, N., First solar air-conditioning system in Cyprus supported by a Fresnel collector.
5th International Conference on Renewable Energy Sources & Energy Efficiency - New Challenges, 5-
6th of May 2016, Nicosia, Cyprus.
OECD/IEA Report "Transition to Sustainable Buildings: Strategies and Opportunities to 2050, Paris, 2013.
OECD/IEA Report "Heating without Global Warming: Market Developments and Policy Considerations for
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Papanicolas, C., Lange, M. A., Fylaktos, N., Montenon, A., Kalouris, G., Fintikakis, N., Santamouris, M.
(2015), Design, construction and monitoring of a near-zero energy laboratory building in Cyprus. Advances
in Building Energy Research, 111
Rashad, M., El-Samahy, A., Daowd, M., Amin, A., A comparative study on photovoltaic and concentrated
solar thermal power plants. EUROSUNMED Symposium, Advanced materials and technologies for
renewable energies (AMREN-1), EMRS Conference, Lille, France, 14-15 May 2015
Serrano-López, R., Fradera, J., Cuesta-López, S., Molten salts database for energy applications, Chemical
Engineering and Processing: Process Intensification, 73, 87-102, 2013.
Vasta, S., Frazzica, A., Freni, A.,Venezia, L., Buscemi, A., Paredes, F., Montagnino, F. M., A concentrating
based solar cooling system for agri-food industry, Acts of 5th International Conference Solar Air-
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... Fig. 9 is showing the better performance of the system after the installation of the storage (in red) both in the daily temperature cycle and the solar fraction. Solar concentrating collectors have been widely implemented in the STS-Med project, supported by the ENPI-CBCMED program, with the construction of 4 building or settlement integrated pilot plants, which are respectively, in Palermo (Italy), Aglantzia (Cyprus), Markaz Belbes (Egypt) and Irbid (Jordan) (Montenon et al. 2016). The aim was to demonstrate the approach towards solar poly-generation (combined heat, cold and electricity) for Mediterranean communities. ...
... The adoption of concentrating optics and high-efficiency thermal cycles can also mitigate the collector footprint, and allow the double utilization of the covered area as the partial and dynamic shadowing is not compromising the soil. As an example, the average footprint of the pilot plants Palermo under the STS-Med project (Montenon et al. 2016) is around 14 m 2 per cooling kW, that is already sensibly lower than the most efficient solution prospected by Otanicar et al. (2012). ...
... Schematic layout of the poly-generative STS-Med demo plant in Palermo. Cited fromMontenon et al. (2016). ...
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The present study evaluates the potential upgrade of a Linear Fresnel Reflector (LFR) collector at the Cyprus Institute (CyI) with photovoltaics via the calculation of the Levelized Cost Of Heat (LCOH). For over 4 years the collector has been supplying heating and cooling to the Novel Technologies Laboratory (NTL) of the Cyprus Institute (CyI). Extensive measurements have been carried out both on the LFR and NTL to render real numbers in the computations. This hybridization would be undertaken with the installation of PV arrays under mirrors, so that the collector is able to either reflect direct radiation to the receiver to process heat or to produce electricity directly in the built environment. The main objective is the decrease of the LCOH of Linear Fresnel collectors, which hinders their wider deployment, while air conditioning demand is globally booming. The results show that the LCOH for a small LFR to supply air conditioning is high, c€25.2–30.1 per kWh, while the innovative PV hybridization proposed here decreases it. The value of the study resides in the real data collected in terms of thermal efficiency, operation, and maintenance.
... They concluded 23.2% energy and 6.2% exergy efficiencies. Montenon et al. [8] investigated a trigeneration system based on a linear Fresnel reflector (LFR) solar system for power, heating and cooling as utilities, and analyzed the performance of the system for use in Italy, Cyprus, Jordan and Egypt. They utilized a RC in Jordan case, and an ORC for other countries for power generation. ...
Conference Paper
In this study, a novel concentrated solar thermal energy driven renewable energy system for multi-generation products is proposed and analyzed. Analysis is performed for the summer daytime climatic conditions of both the selected cities of Antalya, Hatay and Kahramanmaras and Mediterranean region in Turkey. A heliostat field and solar tower-based intercooling-regenerative open Brayton cycle is used as the primary power cycle. Two organic Rankine cycles are coupled to utilize the waste heat of the intercooling and the exhaust of the topping cycle. To produce multi-generation products of power, cooling, green hydrogen, fresh water, industrial process heating and domestic hot water, the proposed plant is incorporated with an electrolyzer, a multi-effect desalination system, an absorption chiller cycle, an industrial process heater and a domestic hot water chamber. Study is per-formed with energy, exergy and environmental analyses to examine the system performance. A detailed parametric analysis is carried out to investigate the effects of variation of some important design parameters on the performance indicators of energy efficiency, exergy efficiency, exergetic quality factor (EQF) and emission savings for the proposed plant considering the climatic conditions of the selected cities. Multiobjective optimization of the proposed plant is conducted to determine the optimum operating conditions of the plant. The proposed MG system has energy and exergy efficiencies and exergetic quality factor of 49.37%, 39.63% and 57.12%, respectively, while it saves 266.1 kg CO2 emissions per hour. The optimized system operates at the highest performance in Kahramanmaras among analyzed cities.
... Furthermore, it can minimize the use of oil and coal and consequently, avoid the hazardous environmental consequences of such conventional sources. One of the aspects or characteristics while researching solar cooling systems is the connection between the resource availability and demand [2], [3]. Air-conditioning based solar energy can be accomplished using either solar thermal or solar photovoltaic (PV) systems. ...
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In the recent years, solar cooling technologies for buildings have garnered increased attention. This study aimed to evaluate the performance of current solar thermal and solar photovoltaic (PV) air-conditioning technologies. Hence, the annual heating/cooling load profile and energy consumption of a reference building in the climate of Aqaba, Jordan were simulated using the TRNSYS software. The solar thermal and solar PV air-conditioning systems were designed and simulated to compensate the cooling demands. It was found that the annual cooling energy accounted for 96.3 % of the total annual energy demand (heating plus cooling) of the reference building. The solar PV and solar thermal air-conditioning systems compensated for direct cooling by 35.8 % and 30.9 %, respectively, and the corresponding compensations of cooling energy by the storage system were 7.3 % and 11.9 %, respectively. Thus, through this comparative study, we found that the storage system significantly contributed in compensating the cooling demands of the solar thermal system; however, the compensation to direct cooling was lower relative to the solar PV system
... In a recent European Union-funded project, Small scale Thermal Solar districts for Mediterranean communities, a solar multigeneration approach has been implemented in four countries (Cyprus, Egypt, Jordan, and Italy). Each plant is characterised by specific components designs and integration scenarios [28]. The LFR plant installed in Egypt is located at SEKEM Medical Centre near Belbis city. ...
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This study reports on the development and implementation of the fuzzy incremental controller on a small-scale linear fresnel reflector solar plant. The control problem is concerned with forcing the output temperature to follow the reference, despite the existence of disturbances. Owing to the non-linear effects of solar plants, the capability of fixed parameters of the proportional–integral controller to cope with the control problem is limited and leads to unsatisfactory control performance. The proposed controller is a modification to a conventional proportional–integral algorithm with better tuning flexibility. Firstly, the ant colony optimisation algorithm is used to define the optimal parameter of proportional–integral plus series feed-forward controller while guaranteeing a satisfactory performance of the plant. Secondly, the resulting controller is replaced with an equivalent fuzzy knowledge-based controller with the error and change of error of the plant as the input variables and flow rate as an output variable. The proposed controller is tested on a quasi-dynamic model of linear fresnel reflector plant using conventional and renewable energy optimisation toolbox in the environment of MATLAB/Simulink. The controller's performance is compared to the proportional–integral controller, where its effectiveness is evaluated under nominal conditions, measurement delay, noise, and presence of disturbance.
... As recent research developments and worldwide installations have demonstrated, CSP are promising technologies for power generation [14]. Through 4 pilot installations, the application of concentrated solar power technologies in small and middle scale installations with the possibility of multi-generation, has been demonstrated [15]. ...
Conference Paper
Renewable energy production technologies are indispensable to the development of a clean and energy efficient built environment. Being dependent on climatic parameters, renewable energy production may vary causing a mismatch between energy demand and available production. Therefore, forecasting of renewable energy production allows the design and implementation of management schedules depending on expected production, thus assisting towards a more efficient and secure operation. The application of artificial neural networks (ANN) has been proved effective towards this aim. The present work is investigating the application of ANN for production forecasting of a concentrated solar power (CSP) fresnel system. The fresnel system production is optimum under clear skies and peak direct solar radiation. The system under investigation is connected to a thermal storage and its production is used to cover the heating/cooling loads of a building. The prediction can be used for scheduling the times that the system focalizes and de-focalizes for optimizing energy production and storage. The present work is relevant to researchers, engineers and developers of renewable energy production technologies that work on optimization of energy production and management. This work can be extended to smart grid energy management.
... As recent research developments and worldwide installations have demonstrated, CSP are promising technologies for power generation [14]. Through 4 pilot installations, the application of concentrated solar power technologies in small and middle scale installations with the possibility of multi-generation, has been demonstrated [15]. ...
Conference Paper
Renewable energy production technologies are indispensable to the development of a clean and energy efficient built environment. Being dependent on climatic parameters, renewable energy production may vary causing a mismatch between energy demand and available production. Therefore, forecasting of renewable energy production allows the design and implementation of management schedules depending on expected production, thus assisting towards a more efficient and secure operation. The application of artificial neural networks (ANN) has been proved effective towards this aim. The present work is investigating the application of ANN for production forecasting of a concentrated solar power (CSP) fresnel system. The fresnel system production is optimum under clear skies and peak direct solar radiation. The system under investigation is connected to a thermal storage and its production is used to cover the heating/cooling loads of a building. The prediction can be used for scheduling the times that the system focalizes and de-focalizes for optimizing energy production and storage. The present work is relevant to researchers, engineers and developers of renewable energy production technologies that work on optimization of energy production and management. This work can be extended to smart grid energy management.
... The utilization of solar energy for heating and cooling applications seems to be an attractive solution that can participate to increase the renewable energy shares in building energy consumption while reducing the consumption of fossil fuel and the environmental impacts of conventional systems. One of the main motivations of the investigation of solar cooling systems is the coincidence of energy availability (solar radiation) and the cooling demands of most buildings (Osama Ayadi et al., 2012b;Montagnino, 2017;Montenon et al., 2016;Motta et al., 2006). ...
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The efficient and productive operation of a Concentrating Solar Thermal (CST) plant depends upon knowledge of the mean reflectance of the solar collector field, as the levelized cost of electricity has a one-to-one ratio with reflector optical performance. Considering the size of such collector fields, a continuous detailed survey of the whole field is not a practical proposition. This paper presents a statistical approach to measuring mean field reflectance by sampling only a subset of the field reflectors. We find that three samples are sufficient for evaluating the mean reflectance of a single facet, and that the locations sampled within the facet do not impact the estimate of the mean. Further, for any collection of facets behaving as a cluster, again sampling three facets is sufficient to yield an estimate of the mean reflectance of the cluster. These sample numbers hold for an error of 2.5% at 95% confidence; different error or confidence intervals will affect the sample numbers required. The results are obtained from studying the behavior of both a heliostat and a linear Fresnel collector field. A blueprint for large CST collector fields is derived.
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The study offers updated and more accurate information about long-term annual solar resource in the most countries of Europe, Middle East and North Africa (EU-MENA) and evaluates PV power production potential. The underlying solar radiation and PV electricity output values are calculated form the solar and meteo database SolarGIS, which covers a history of recent 18 years. Direct Normal Irradiation data are presented to indicate potential of Concentrated PV in the region. PV electricity output is calculated for c-Si module options, using the recent numerical models. The analysis is focused on the urbanized and industrial areas and their hinterland. Attention is focused also to the quantification of uncertainty. Based on the GIS analysis, the solar resource potential of each country is rated.
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In the framework of the STS-Med Project funded by European Commission under the ENPI CBCMED program, four solar polygenerative plants have been designed to be connected with public buildings in four different Mediterranean countries, respectively Italy, Cyprus, Egypt, and Jordan. All the plants are characterized by an innovative application of concentrating solar collectors with the aim to generate a balanced answer to the energy demanded by the buildings: electricity, heat and cold, as well as other energy driven services like the supply of purified water. One of the project goals is to investigate the different components that can be effectively combined in zero or positive energy districts, both in built and rural environments. In part A of this work, the designs of the Italian plant is presented while in this the Jordanian plant is presented. Each design is characterized by different collecting technologies, respectively Linear Fresnel and Parabolic Trough, a distinct context of installation of the solar field, on ground and on roof, and a polygeneration balance which has been tuned accordingly with the specificity of the two sites. Both designs were based on the results of the energy audits performed on both sites. They showed the prevalence of the summer cooling demand. The installation constraints, as the size and the orientation of the available space, have driven the design of the plants and the selection of the possible storage and conversion technologies. In the Italian plant, an innovative LFC solar field has been introduced, as well as a thermal energy storage unit that is downscaling the molten salts large TES units, typically applied in utility scale CSP plants. The Jordanian designers have introduced a steam circuit that feed a steam turbine manufactured at a very small scale. Conclusions are drawn and documented about the potential impact of solar polygeneration in the Mediterranean solar belt and the future development of the involved technologies. Results showed that the Italian CS plant has a Utilization Factor of 0.7 and the Jordanian Plant 0.62.
Book
Concentrating solar power (CSP) technology is poised to take its place as one of the major contributors to the future clean energy mix. Using straightforward manufacturing processes, CSP technology capitalises on conventional power generation cycles, whilst cost effectively matching supply and demand though the integration of thermal energy storage. Concentrating solar power technology provides a comprehensive review of this exciting technology, from the fundamental science to systems design, development and applications. Part one introduces fundamental principles of concentrating solar power systems. Site selection and feasibility analysis are discussed, alongside socio-economic and environmental assessments. Part two focuses on technologies including linear Fresnel reflector technology, parabolic-trough, central tower and parabolic dish concentrating solar power systems, and concentrating photovoltaic systems. Thermal energy storage, hybridization with fossil fuel power plants and the long-term market potential of CSP technology are explored. Part three goes on to discuss optimisation, improvements and applications. Topics discussed include absorber materials for solar thermal receivers, design optimisation through integrated techno-economic modelling, heliostat size optimisation, heat flux and temperature measurement technologies, concentrating solar heating and cooling for industrial processes, and solar fuels and industrial solar chemistry. With its distinguished editors and international team of expert contributors, Concentrating solar power technology is an essential guide for all those involved or interested in the design, production, development, optimisation and application of CSP technology, including renewable energy engineers and consultants, environmental governmental departments, solar thermal equipment manufacturers, researchers and academics.
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The paper presents the architectural, engineering and energy design of a laboratory building located in Cyprus. The building is designed to meet near-zero energy consumption criteria using advanced energy conservation measures, smart energy management and solar thermal and photovoltaic systems to cover the remaining energy load. The energy conservation techniques used result in reduced energy consumption of the building by almost 70% compared with a conventional building, while almost 27% of the remaining heating-, cooling- and lighting load is covered by photovoltaics. A concentrating solar thermal system for cooling and heating is being installed to cover the remainder of the load.
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DOWLOAD THE FINAL PUBLISHED VERSION HERE: http://dx.doi.org/10.1016/j.cep.2013.07.008 The growing interest in energy applications of molten salts is justified by several of their properties. Their possibilities of usage as a coolant, heat transfer fluid or heat storage substrate, require thermo-hydrodynamic refined calculations. Many researchers are using simulation techniques, such as Computational Fluid Dynamics (CFD) for their projects or conceptual designs. The aim of this work is providing a review of basic properties (density, viscosity, thermal conductivity and heat capacity) of the most common and referred salt mixtures. After checking data, tabulated and graphical outputs are given in order to offer the most suitable available values to be used as input parameters for other calculations or simulations. The reviewed values show a general scattering in characterization, mainly in thermal properties. This disagreement suggests that, in several cases, new studies must be started (and even new measurement techniques should be developed) to obtain accurate values.
First solar air-conditioning system in Cyprus supported by a Fresnel collector
  • A Montenon
  • N Fylaktos
Montenon, A., Fylaktos, N., First solar air-conditioning system in Cyprus supported by a Fresnel collector.
A comparative study on photovoltaic and concentrated solar thermal power plants
  • M Rashad
  • A El-Samahy
  • M Daowd
  • A Amin
Rashad, M., El-Samahy, A., Daowd, M., Amin, A., A comparative study on photovoltaic and concentrated solar thermal power plants. EUROSUNMED Symposium, Advanced materials and technologies for renewable energies (AMREN-1), EMRS Conference, Lille, France, 14-15 May 2015
A concentratingbased solar cooling system for agri-food industry
  • S Vasta
  • A Frazzica
  • A Freni
  • L Venezia
  • A Buscemi
  • F Paredes
  • F M Montagnino
Vasta, S., Frazzica, A., Freni, A.,Venezia, L., Buscemi, A., Paredes, F., Montagnino, F. M., A concentratingbased solar cooling system for agri-food industry, Acts of 5th International Conference Solar Airconditioning, Germany, 2013