scholarly journals Small Scale Solar Cooling Unit in Climate Conditions of Latvia: Environmental and Economical Aspects

Author(s):  
Dzintars Jaunzems ◽  
Ivars Veidenbergs

Small Scale Solar Cooling Unit in Climate Conditions of Latvia: Environmental and Economical Aspects The paper contributes to the analyses from the environmental and economical point of view of small scale solar cooling system in climate conditions of Latvia. Cost analyses show that buildings with a higher cooling load and full load hours have lower costs. For high internal gains, cooling costs are around 1,7 €/kWh and 2,5 €/kWh for buildings with lower internal gains. Despite the fact that solar cooling systems have significant potential to reduce CO2 emissions due to a reduction of electricity consumption, the economic feasibility and attractiveness of solar cooling system is still low.

2021 ◽  
Vol 11 (2) ◽  
pp. 511
Author(s):  
Aiman Albatayneh ◽  
Mustafa Jaradat ◽  
Murad Al-Omary ◽  
Maha Zaquot

When they were first conceived, solar cooling systems were designed to be cost-effective and environmentally safe alternatives for the majority of the developing nations that are characterised by their hot climates in contrast with the traditional air conditioning systems powered by electricity that is produced from fossil fuel resources. Nevertheless, developments in photovoltaic (PV) and air-conditioning technologies have impacted on the prospects of solar cooling systems. This study examined two different options: a coupled PV and air conditioner system and a solar cooling system (absorption chillers where thermal energy is provided by solar collectors) for a specific developing country located in the Eastern Mediterranean region whose climate is hot and dry (Jordan). The cooling system comprised a pair of cooled multistage compression, both of which were 700 kW, while the PV system’s size was 2.1 MWp, the utility grid connection was a 0.4 kV 50 Hz net meter (2 m) and it was anticipated that 3300 MWh/year would be generated. The solar cooling system operated at a maximum coefficient of performance (COP) of 0.79 and had an actual recorded COP of 0.32 on the site; when the electricity tariff of $0.1/kWh was considered, the respective levelised cost of energy (LCOE) values were $0.9/kWh and $2.35/kWh respectively. The findings indicate that the initial costs for the solar thermal cooling system and the PV system were approximately $3.150M and $3M, respectively. The current value of future cash payments when discounts of 6% per year were applied to the payments for the combination of PV and air conditioning was about $9,745,000, whereas the solar thermal cooling system will not reach the breakeven point at negative $1,730,000. It is clear the absorption chiller did not display economic feasibility, whereas the value for the coupled PV and air-conditioning systems was under $0.05/kWh. In addition to the extensive maintenance needs, the reduced COP and the practicality and feasibility of the solar thermal cooling systems mean these kinds of technologies are under significant pressure to remain competitive when faced with the development of new air conditioning and PV technologies.


2010 ◽  
Vol 297-301 ◽  
pp. 802-807
Author(s):  
Nadia Allouache ◽  
Rachid Bennacer ◽  
Salahs Chikh ◽  
A. Al Mers

The present study deals with a solid adsorption refrigerator analysis using activated carbon/methanol pair. It is a contribution to technology development of solar cooling systems. The main objective consists to analyse the heat and mass transfer in an annular porous adsorber that is the most important component of the system. The porous medium is contained in the annular space and the adsorber is heated by solar energy. A general model equation is used for modelling the transient heat and mass transfer. Effects of the key parameters on the adsorbed quantity, the coefficient of performance, and thus on the system performance are analysed and discussed.


1983 ◽  
Vol 105 (2) ◽  
pp. 217-223
Author(s):  
M. L. Warren ◽  
M. Wahlig

Economic and thermal performance analyses of typical residential and commercial active solar cooling systems are used to determine cost goals for systems to be installed between the years 1986 and 2000. Market penetration for heating, ventilating, and air conditioning systems depends on payback period, which is related to the expected real return on investment. Postulating a market share for solar cooling systems increasing to 20 percent by the year 2000, payback and return on onvestment goals as a function of year of purchase are established. The incremental solar system cost goal must be equal to or less than the 20-year present value of future energy savings, based on thermal performance analysis, at the desired return on investment. Methods for achieving these cost goals and expected solar cooling system costs will be discussed.


Author(s):  
Tianyi Gao ◽  
James Geer ◽  
Bahgat G. Sammakia ◽  
Russell Tipton ◽  
Mark Seymour

Cooling power constitutes a large portion of the total electrical power consumption in data centers. Approximately 25%∼40% of the electricity used within a production data center is consumed by the cooling system. Improving the cooling energy efficiency has attracted a great deal of research attention. Many strategies have been proposed for cutting the data center energy costs. One of the effective strategies for increasing the cooling efficiency is using dynamic thermal management. Another effective strategy is placing cooling devices (heat exchangers) closer to the source of heat. This is the basic design principle of many hybrid cooling systems and liquid cooling systems for data centers. Dynamic thermal management of data centers is a huge challenge, due to the fact that data centers are operated under complex dynamic conditions, even during normal operating conditions. In addition, hybrid cooling systems for data centers introduce additional localized cooling devices, such as in row cooling units and overhead coolers, which significantly increase the complexity of dynamic thermal management. Therefore, it is of paramount importance to characterize the dynamic responses of data centers under variations from different cooling units, such as cooling air flow rate variations. In this study, a detailed computational analysis of an in row cooler based hybrid cooled data center is conducted using a commercially available computational fluid dynamics (CFD) code. A representative CFD model for a raised floor data center with cold aisle-hot aisle arrangement fashion is developed. The hybrid cooling system is designed using perimeter CRAH units and localized in row cooling units. The CRAH unit supplies centralized cooling air to the under floor plenum, and the cooling air enters the cold aisle through perforated tiles. The in row cooling unit is located on the raised floor between the server racks. It supplies the cooling air directly to the cold aisle, and intakes hot air from the back of the racks (hot aisle). Therefore, two different cooling air sources are supplied to the cold aisle, but the ways they are delivered to the cold aisle are different. Several modeling cases are designed to study the transient effects of variations in the flow rates of the two cooling air sources. The server power and the cooling air flow variation combination scenarios are also modeled and studied. The detailed impacts of each modeling case on the rack inlet air temperature and cold aisle air flow distribution are studied. The results presented in this work provide an understanding of the effects of air flow variations on the thermal performance of data centers. The results and corresponding analysis is used for improving the running efficiency of this type of raised floor hybrid data centers using CRAH and IRC units.


2018 ◽  
Vol 22 (5) ◽  
pp. 2151-2162
Author(s):  
Jose Marcos ◽  
Raquel Lizarte ◽  
Fernando Varela ◽  
Maria Palacios-Lorenzo ◽  
Ana Blanco-Marigorta

A solar cooling system with an optimized air-cooled double-effect water/LiBr absorption machine is proposed as a sustainable alternative to meet cooling demands in dry hot climates. This system allows eliminating the cooling towers in those regions of the planet where water is scarce. This work analyses the environmental benefits of this air-cooled system, as well as its environmental foot-prints, compared to a solar water-cooled single effect. In this regard, a methodology has been applied to calculate the annual saving in water consumption produced in a case study: a hospital located in Almer?a, in South of Spain. Further-more, the reduction in energy consumption and CO2 emissions is also quantified since this machine can be driven by solar energy and with higher efficiency than those of single effect.


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