Annual Average Coefficient Of Performance Research Articles

Economic optimization and thermodynamic analysis of a novel nuclear district cooling system

“Yanlong” pool-type low-temperature heating reactor (DHR-400) stands at a highly promising nuclear heating technology. However, its annual utilization duration faces constraints when exclusively employed for winter heating. To cope with this challenge, a novel nuclear district cooling system driven by DHR-400 is proposed for the first time in this paper. As the core component of the proposed nuclear district cooling system, single-effect double-lift LiBr-H2O absorption refrigeration system (SDARS) can significantly increase the temperature difference between the supply and return of the primary heating network (PHN), thereby reducing the transmission energy consumption. Despite the significant potential, the optimization design of SDARS has received limited attention. An optimization model for SDARS with the annual cost (AC) as the objective function is developed. Focusing on a real district cooling scenario in Xi'an High-tech Zone, the heat transfer areas of all process units and the operating parameters of all streams in SDARS are optimized. Results demonstrate that the optimal annual average coefficient of performance (AACOP) is improved by 10.63 % and AC is reduced by 5.44 % compared with the Benchmark case. The dynamic payback period for the combined heating and cooling system driven by DHR-400 is reduced by 5.53 years compared to the heating-only system.

Research on Energy Savings of an Air-Source Heat Pump Hot Water System in a College Student’s Dormitory Building

Centralized hot water systems are commonly installed in college student dormitories, representing a typical application for such systems. To achieve sustainable and environmentally friendly heating solutions, air-source heat pump hot water systems have gained attention for their high efficiency and energy-saving characteristics. By implementing heat pump technology, China could make significant progress towards achieving its carbon neutrality goals by reducing energy consumption and associated emissions. In this study, the heating performance of an air-source heat pump hot water system was tested in the field over the course of a year at a university in Chongqing, China. A simulation model was constructed using TRNSYS software, and a time-sharing control strategy was proposed to analyze the system’s operating characteristics and energy-saving performance. Results showed a 6% increase in unit annual average Coefficient of Performance (COP) and annual electricity savings of 10,027 kW·h, with an energy-saving rate of 8.77% after time-sharing control. The study highlights the significant economic and environmental benefits of adopting sustainable energy solutions, particularly in the context of increasing global greenhouse gas emissions.

Analysis of a solar-assisted heat pump system with hybrid energy storage for space heating

Insufficient heating capacity and low coefficient of performance have always been obstacles that inhibit the application of air source heat pump systems in cold regions. This study proposes an indirect expansion solar-assisted air source heat pump system to improve the heating performance of the air source heat pump. The indirect expansion solar-assisted air source heat pump system consists of solar collectors, a hybrid thermal energy storage tank, and a dual-source heat pump. An optimized control method is proposed to tackle the refrigerant redistribution problem for the dual-source heat pump. An experiment is carried out to study the thermodynamic performance of the indirect expansion solar-assisted air source heat pump. The experimental results indicate that the average coefficient of performance of the solar heat pump mode is increased by 50.0% compared to the air source heat pump mode due to the higher evaporating temperature. Based on the experimental results, a techno-economic and environmental analysis of the indirect expansion solar-assisted air source heat pump system for space heating is conducted in six northern cities in China. The indirect expansion solar-assisted air source heat pump system has the highest annual average coefficient of performance of 2.53 in Jinan, which is increased by 18.8% compared to Harbin. The payback period of the indirect expansion solar-assisted air source heat pump system is shortest in Xining and is reduced by 53.45% compared to Jinan. Applying the IX-SAASHP system in the northwest region is suitable for improving its energy and economic performance. The analysis results indicate that the IX-SAASHP system is beneficial for reducing carbon emissions from space heating systems in the northeast region.

Green ground source heat pump using various low-global-warming-potential refrigerants: Thermal imbalance and long-term performance

Ground source heat pump is a promising technology for achieving carbon neutrality in the building sector owing to its high energy efficiency in heating and cooling applications. To mitigate global warming, low-global-warming-potential refrigerants are explored as long-term substitutes for ground source heat pumps. However, few studies have examined the long-term characteristics of green ground source heat pump systems using low-global-warming-potential refrigerant. This work fills this gap by comparing the long-term performance of ground source heat pump systems using typical low-global-warming-potential hydrofluorocarbon and hydrofluoroolefin refrigerants, with the conventional R134a as a baseline. Results show that the ground source heat pump system with R161 has the smallest thermal imbalance ratio, while the ground source heat pump system with R1234ze(E) suffers from the largest. Compared to R134a, R161 and R1234yf relieve the soil thermal imbalance, while R152a and R1234ze(E) exacerbate the imbalance. After 10 years of operation, the average soil temperature decreases from 10.40 °C to 9.82 °C, 9.58 °C, 9.41 °C, 9.16 °C, and 9.09 °C for R161, R1234yf, R134a, R152a, R1234ze(E), respectively. R1234ze(E) yields the highest annual average coefficient of performance of 4.16–4.20, while R161 shows the lowest value of 3.55–3.56. Compared to R134a, R152a and R1234ze(E) improve the annual coefficient of performance, while R161 and R1234yf degrade it. This work could guide the rational development of green ground source heat pump technologies using promising low-global-warming-potential refrigerants to achieve low environmental impact and high energy efficiency.

Study on the influence of buried pipe fault on the operation of ground source heat pump system

In order to analyze the influence of fault buried pipes on the operation of ground source heat pump system, a simulation model of unit considering both the influence of inlet fluid flow and temperature is developed, which is coupled with the three-dimensional dynamic model of 3 × 3 pipe group. The results show that the influence degree caused by different blocked positions is basically same. When one, two and a group of pipes are blocked, the annual power consumption of unit increases by 3.78%, 8.81% and 15.91% respectively. Besides, the system annual average coefficient of performance decreases from 3.28 to 3.21, 3.12 and 2.98. The ratio of cooling to heating load demands studied is 1.44, and the pipe blockage exacerbates the soil thermal imbalance, which cause a continuous deterioration of cooling performance. When the cooling load is high, the system is difficult to meet the demand. Because of design margin of total length, the time for not meeting the cooling demand after blocking one pipe is the same as normal condition, but the time after blocking two and a group of pipes increases 37.5 h and 88.5 h. Moreover, the amount for not meeting the demand increases 25.4%, 52.11% and 129.94% on average respectively.

Experimental study on a novel pump-driven heat pipe/vapor compression system for rack-level cooling of data centers

Conventional air-conditioners in data centers generally have the problems of high energy consumption and poor cooling effect. In this paper, a composite cooling system with pump-driven heat pipe and vapor compression operation modes is proposed to solve the above problems. The system adopts pump supply liquid technology and rack-level terminals. The cooling effect, energy efficiency, and annual performance of the system are analyzed in this paper. In terms of energy efficiency, the coefficient of performance in vapor compression mode is 6.6–3.8 (outside temperature is 15–35 °C); the coefficient of performance in heat pipe mode is 15.8–9.7 (outside temperature is −15–15 °C). In terms of the cooling effect, the novel system performs well for temperature control accuracy, and the on-demand supply cooling of each rack can be realized. In terms of the annual performance of the typical city, the annual average coefficient of performance of the novel system in vapor compression mode increases by 8.5% compared with the system adopting direct expansion technology. The power usage effectiveness of the data center that adopts the novel cooling system can reach 1.23 which satisfies the current standard.

Numerical investigation of geothermal pavements: Design optimisation & boundary conditions

Geothermal pavements comprise a newfound type of thermal geo-structures, an innovation in pavement construction contributing to ground source heat pump (GSHP) systems, resulting in a better cost-efficiency compared to conventional GSHP systems. Ground heat exchangers are formed by embedding pipe into the pavement structure (e.g., base, sub-base or subgrades). Developing accurate models with appropriate boundary conditions is crucial to obtaining a deep understanding of the performance and function of geothermal pavement systems. This paper introduces an experimentally validated 3D finite element model (FEM) and compares the effect of surface boundary condition choices on the results of the simulation. The model uses two different approaches for boundary conditions: i) using ambient temperature and ii) implementing energy balance equations on the surface, as surface boundary conditions. The model is further utilised to perform a parametric study and the results are employed by a statistical tool (Minitab) to determine the optimum heat exchanger design for a geothermal pavement project in Adelaide, an Australian city subjected to temperate climate conditions and good solar irradiation throughout the year. Results show that the choice of both boundary conditions leads to similar fluid temperature trends, but with differences in values, particularly during the heating season, resulting in a reduced embedded pipe length of up to 30 % and up to a 10 % better annual average coefficient of performance (COP(when using the energy balance equations on the surface. The parametric study shows that the system annual COP increases with the length of the pipe and spacing between the pipes, whilst the pipe depth placement is inversely proportional to the annual average COP given the advantages obtained during the heating season over the cooling season. Finally, considering the interaction effect between various parameters, a pipe heat exchanger with 400 m length, 0.76 m pipe spacing and 0.45 burial depth is evaluated as the best design to maximise COP for the case study at hand.

Potential application of cascade adsorption-vapor compression refrigeration system powered by photovoltaic/thermal collectors

• Cascade adsorption-compression system is investigated using photovoltaic thermal collectors. • Overall performance enhancement is attained at higher chilled water temperatures. • Annual energy saving proportionally increases with collector numbers up to 29%. • Distinctive payback period is attained compared to the state-of-the-art systems. In the present study, a theoretical assessment of an adsorption-assisted cascade compression refrigeration system powered by photovoltaic/thermal collectors is performed. The proposed system is intended to produce refrigeration and electricity simultaneously. Herein, mathematical modeling of the proposed system is developed using MATLAB/SIMULINK and validated with the open literature. The impact of collector area, compressor displacement volume, cooling water temperature, and brine temperature on the system performance are quantitatively investigated and analyzed. The economic analysis of the proposed system has also been conducted. It is observed that decreasing the compressor displacement volume and cooling water temperature could substantially increase the overall coefficient of performance and energy saving. Furthermore, the results demonstrate that the system performance enhances with the increase of the collector area and the brine temperature. It is found that the proposed system can concurrently attain a daily average cooling capacity and electricity yield of 1.7 kW and 103 kWh at cooling and brine temperatures of 30 °C and −20 °C, respectively. Simulation results indicate that the proposed system can generate annual refrigeration production and electricity production of 34.4 kWh c m −2 and 213 kWh el m −2 , respectively, with an annual average coefficient of performance of 2.38. Moreover, the economic analysis exhibited that the photovoltaic/thermal collectors-assisted cascade adsorption-compression system is economically competitive for refrigeration applications, revealing an annual energy saving of 24.8% and a payback period of ∼3.9 years. In this regard, cascade adsorption-compression systems could significantly extend the potential application and energy savings for cooling systems and heat pumps.

Customized data center cooling system operating at significant outdoor temperature fluctuations

This elaboration presents the configuration of the cooling system of the POLCOM Data Center which utilizes commercially available components, proposes steering strategy and analyzes their functionality. The designed architecture of cooling and dedicated control system is presented to demonstrate the novelty and customization with respect to the demanding outdoor temperatures existing in the climate of the Małopolska Province. The cooling system control and operation is illustrated by a comprehensive analysis of compressor and freecooling modes. The discussion on embedded functionality of chillers is undertaken. According to features and limitations of the complex solution, the cooling system reached the annual average coefficient of performance of 8.63 in 2015 (increase of 110% compared to the year 2014), operating 65% of the time during the year in compressor mode and 35% in freecooling mode. This coefficient in compressor mode amounted to 4.39 while in freecooling mode totaled 16.50. It was proved that in the real case under consideration they generated losses in electricity consumption amounting to 557MWh per year. The real-time experimental data collected from the commercial Data Center installation are used to present a unique operation of a such complex system.

Thermoeconomic analysis of CO2 Ejector-Expansion Refrigeration Cycle (EERC) for low-temperature refrigeration in warm climates

Refrigeration industry is adopting a proactive strategy to phase out fluorinated greenhouse gases by more sustainable working fluids. R744 is a natural refrigerant widely proposed for commercial refrigeration. Its use in cascade and booster cycles allows a combined cooling and freezing production. However, when single-stage evaporation at low temperature is required, the adoption of R744 in transcritical cycles is scarce. The main reasons are due to the low Coefficient of Performance (COP) achieved, as well as the technical limitations to reach extreme pressure ratios using commercial compressors. In light of this, this paper proposes to use the CO2 Ejector-Expansion Refrigeration Cycle (EERC) to overcome these drawbacks. To assess the feasibility of the proposal, a thermoeconomic optimization is conducted for low-temperature refrigeration in warm climates. The analysis has been conducted considering a two-phase flow ejector, a commercial double-stage compressor, and evaporating conditions ranging from −10 °C to −38.11 °C, which was revealed the minimum temperature to avoid the triple point inside the ejector. The results showed that the EERC allows using smaller commercial compressors within a broader operating envelope, improving the annual average COP about 5.5% compared to the reference cycle, besides reducing investment and yearly energy consumption costs.

Energy benefit of organic Rankine cycle in high-rise apartment building served by centralized liquid desiccant and evaporative cooling-assisted ventilation system

Building heating, ventilating, and air-conditioning systems have high impacts on the energy and environmental performance of residential buildings. To reduce the energy consumption of the building for sustainable buildings and cities, this research proposed the organic Rankine cycle (ORC) applied to a centralized liquid desiccant (LD) and evaporative cooling-assisted ventilation system serving an apartment building and evaluated the energy impact of the proposed system via detailed energy simulations. As a small combined heat and power application in residential buildings, the ORC produces heat and power that are consumed by the proposed system and the building. A conventional decentralized energy recovery ventilator powered by the existing power grid was selected as a reference system. The combination of the ORC, LD, and evaporative cooling-assisted ventilation system allows decoupling of the sensible and latent cooling and offers energy benefits by reclaiming heat from the ORC compared with the reference system owing to the parallel system of energy consumption. Energy simulations were conducted for one floor of a 30-story apartment building. The proposed system exhibited 28% annual primary energy savings and provided a 54% higher annual average coefficient of performance compared with the reference system, although the proposed system consumed more fan and pump energy. The majority of the operating energy savings of the proposed system were achieved by reclaiming the waste heat from the ORC condenser.

Study on model uncertainty of water source heat pump and impact on decision making

Water source heat pump systems are widely used for cooling and heating due to high efficiency. The energy source can be surface water or underground water. Accurate modeling of water source heat pump systems is the basis for performance prediction, design and control optimization. However, various heat pump models are available to predict the system performance and results obtained can be very different under different models due to the model uncertainty. Without considering these uncertainties, the performance of water source heat pump systems would be overestimated or underestimated and the decision making would be affected. This paper attempts to quantify the model uncertainty of water source heat pump and its impact on the system performance. Thirteen commonly-used models are selected and validated using the manufacture data. By importing these models into the water source heat pump system, the impact of heat pump model uncertainty on the system performance is quantified. It shows that the model uncertainty can result in a deviation of up to 30% in the annual energy consumption. The energy saving potential of water source heat pump systems can vary from -18.43% to 14.78% compared with the chillers & boiler in the hot summer and cold winter area. The priority of water source heat pump systems is also controversial. The difference in the annual average coefficient of performance of the system can be up to 1.22. It demonstrates that the model uncertainty of water source heat pumps affects the system performance significantly and should be taken into account in building energy prediction and design optimization. The models considering the correction of part load ratio are recommended.

Designing and Optimizing Heat Storage of a Solar-Assisted Ground Source Heat Pump System in China

The cold accumulation problem can lead to performance degradation of heat pumps. This paper presents the design and optimization of a solar-assisted storage system to solve this issue. A ground source heat pump (GSHP) project was established using the transient system simulation program (TRNSYS) based on a ground heat exchange theoretical model, which was validated by a previously established experiment in Beijing. The Beijing, Harbin, and Zhengzhou regions were used in numerical simulations to represent three typical cities where buildings require space heating (a cold region, a severe cold region, and a hot summer and cold winter region, respectively). System performance was simulated over periods of ten years. The simulation results showed that the imbalance efficiencies in the Beijing, Harbin, and Zhengzhou regions are 55%, 79%, and 38%, respectively. The annual average soil temperature decreases 7.3°C, 11.0°C, and 5.3°C during ten years of conventional GSHP operation in the Beijing, Harbin, and Zhengzhou regions, respectively. Because of the soil temperature decrease, the minimum heating coefficient of performance (COP) values decrease by 23%, 46%, and 11% over the ten years for GSHP operation in these three regions, respectively. Moreover, the simulation data show that the soil temperature would still be decreasing if based on the previous solar energy area calculation method. Design parameters such as the solar collector size are optimized for the building load and average soil temperature in various cold regions. Long-term operation will test the matching rate of the compensation system with the conventional GSHP system. After the system is optimized, the solar collector area increases of 20% in the Beijing region, 25% in the Harbin region, and 15% in the Zhengzhou region could help to maintain the annual average soil temperature balance. The optimized system could maintain a higher annual average COP because of the steady soil temperature. It provides a method for the design of a solar collector area which needs to be determined in the seasonal heat storage solar ground source heat pump system.

Effect of climate conditions on the thermodynamic performance of a data center cooling system under water-side economization

This paper evaluates the potential of water-side economizers in the refrigeration system of data centers under different climate conditions. Due to the wide range of conditions along the country (Desert, Mediterranean, Temperate rainy and Tundra climate), Chile is selected as case study. The number of hours per year in which economization is possible is estimated using the data base of 22 weather stations along the country. The refrigeration system is modeled in steady state through a set of thermodynamic equations simultaneously solved using the Engineering Equation Solver (EES). The system performance is evaluated by calculating the Coefficient of Performance (COP) and the Water to Energy Ratio (WER). The latter is a new metric proposed to compare the volume of water required by the system to save 1 MWh of cooling energy. The thermodynamic analysis shows that the chiller decreases its energy usage if water-side economizers are implemented in favorable climates such as cool-summer Mediterranean with winter rain (Csc), temperate rainy (Cfb) and tundra (ET) climates. Here, the use of economizers allows a monthly increase in the COP of 50 to 120% (compared to the conventional operation) and an annual average COP ranging from 7.8 to 9.7. These climates also offer an additional gain of lower water requirements, with annual WER values ranging from 11 to 17 m3/MWh. Desert climates, on the other hand, prevent implementing economizers, offering the lowest annual average COP values (5.6–5.7). In climates in which the complete economization is impossible, the partial use of economizers allows a monthly increase in the COP of 10 to 45%. The costal influence decreases the system performance, reducing the COP and increasing the WER.

End-users’ and policymakers’ impacts on optimal characteristics of a dew-point cooler

Impacts of end-users’ behavior and policymakers’ decision on the optimal performance characteristics of a dew point cooler are investigated. Acceptable level of thermal comfort, cooling load, and the economic factors, including water and electricity tariffs, and inflation and discount rates, are considered as the effective parameters. The objective functions of the conducted multi-objective optimization, i.e., life-cycle cost, annual water consumption, and annual average coefficient of performance, in addition to the charge paid for the resource consumption throughout the first year are studied as the performance criteria. A benchmark residential building in Ahmedabad, India, is also selected as the case study. Results show that despite paying coefficient of determination penalty, the value of 15% for the maximum allowable predicted percentage dissatisfied is the best thermal comfort level from both economic and resource consumption perspectives. Moreover, in the investigated range of the inflation rate, the four introduced performance criteria change 5.4%, 51.6%, 45.6%, and 33.4% while the corresponding values for discount rate are 10.1%, 58.1%, 84.5%, and 37.1%, respectively. Therefore, performance of the optimum system is more sensitive to the discount rate.

Annual performance analysis of an air source heat pump water heater using a new eco-friendly refrigerant mixture as an alternative to R134a

The air source heat pump water heater (ASHPWH) is an efficient and environmentally friendly system that is widely used in China. In this study, a refrigerant mixture R290/R600a/R13I1 with low global warming potential (GWP) and no ozone depletion potential (ODP) is proposed as drop-in replacement for R134a in ASHPWH. A theoretical model for an ASHPWH is developed based on MABLAB linking with REFPROP. The cycle performances of the proposed mixture, a contrast mixture, and R134a are analyzed under different working conditions, to investigate the feasibility of substitution. The annual performances of the ASHPWH that uses different refrigerants are also studied for comparison. The results show that compared with R134a, the proposed mixture has better performance with lower condensing pressure and compression ratio, and higher specific heating capacity and coefficient of performance (COP). The discharge temperature is also reasonable. Therefore, it is feasible to replace R134a with the proposed mixture. The ASHPWH using the proposed mixture has obvious advantages when the ambient temperature is very low. The annual average COP with the proposed mixture is 4.65, which is about 6.2% higher than with R134a, and the total equivalent warming impact (TEWI) can be reduced by 18.99%.

Employing static and dynamic optimization approaches on a desiccant-enhanced indirect evaporative cooling system

The best possible condition for employing desiccant-enhanced indirect evaporative cooling system (DEVap) as efficient as possible in four cities of Iran is found. To achieve this purpose, both static and dynamic optimization approaches are employed for design as well as retrofit stages, using the combination of non-dominated sorting genetic algorithm II (NSGA-II) and TOPSIS method as the ordering technique by similarity to ideal solution. As a result, four optimization scenarios are defined. Through a comprehensive comparative study among the optimum results, the best optimization strategy for each city is suggested. Both dimensional characteristics and operational parameters of the cooler are considered as decision variables while necessary technical and geometrical constraints such as thermal comfort condition are imposed. In addition, life-cycle cost (LCC), annual average coefficient of performance (ACOP), annual water consumption (AWC), and annual carbon dioxide emission (ACE) are optimized as the objective functions. It is found that for all the four investigated cities and both design and retrofit stages, dynamic optimization approach offers better results. Compared to the base condition, which is the static retrofit optimization, dynamic retrofit optimization results in 23.7, 50.5, 153.2, and 57.8% improvement in LCC, ACOP, AWC, and ACE, respectively. The average enhancement of the four mentioned objective functions for dynamic design optimization are 34.6, 60.1, 390.0, and 69.9%, respectively.

Performance Analysis of a Combined Solar-Assisted Heat Pump Heating System in Xi’an, China

This study proposed a combined solar-assisted heat pump (SAHP) system that could operate in the serial mode or parallel mode. For this proposed system, a stable year-round operation could be achieved without the assistance of electric heating or low-temperature heat pump. By analyzing the heat balance equations, a correlation of the combined SAHP system for the two modes switched was obtained, which provided a theoretical basis for the optimal operation of this system. In addition, the performance of the proposed system applied in a university bathroom in Xi’an district was investigated using TRNSYS. The results illustrated that compared to the serial and parallel systems, the proposed system exhibited a good performance on energy efficiency. The annual average coefficient of performance (COP) of the proposed system was 5.7, obviously higher than those of the serial system and the parallel system, which were 3.3 and 4.3, respectively. Therefore, the results in this study could provide the theoretical guidance and reference for practical engineering design.

Organic Rankine Cycle-assisted ground source heat pump combisystem for space heating in cold regions

This paper presents an Organic Rankine Cycle (ORC)-assisted ground source heat pump combisystem for the cascaded utilization of low-grade energy and shallow geothermal energy in cold regions. The ORC unit was added to conventional ground source heat pumps to solve the cold accumulation problem, which can lead to performance degradation of heat pumps. The existing types and novel types of the combisystem were then modeled with the Transient System Simulation Program (TRNSYS). During the heating season, the ORC unit and heat pump unit were combined for space heating, and during the non-heating season, the ORC unit was connected to ground heat exchangers for seasonal storage. System performance was simulated over periods of one year and twenty years. The twenty-year simulation results showed that the proposed combisystem could maintain a higher annual average coefficient of performance (COP) of approximately 3.8 because of the steady soil temperature, whereas the annual average COP of the conventional ground source heat pump system decreased from 3.7 to 3.2. Additionally, the total power consumption per unit heating area of the heating system decreased from 2.2 × 103 kW·h/m2 to 3.3 × 102 kW·h/m2 when the ORC unit was added to the conventional ground source heat pump. This translates to electricity cost savings of ¥ 908/m2 over twenty years. Moreover, in the combisystem, the ORC unit provides 55.6% of the total heating capacity; compensates for 78.5% of the heat pump unit’s power consumption. And 94.1% of the thermal energy storage from the non-heating season can be used during the heating season by the heat pump unit.

Design and retrofit optimization of the cellulose evaporative cooling pad systems at diverse climatic conditions

Cellulose pad direct contact evaporative coolers (CPDECs) were modeled and optimized. In this regard, a detailed method for evaluation of the initial cost was introduced. This model as well as thermodynamic, hydraulic and other economic ones were employed to minimize the life-cycle cost (LCC) and the annual water consumption (AWC) and maximize the annual average coefficient of performance (AACOP). It was assumed that the CPDEC was employed as the cooling system for a middle flat of a five-story residential building with floor area of 97.1m2. Multi-objective optimization (MOO) imposing proper constraints including thermal comfort was done in two scenarios: design optimization process (DOP, applicable before production) and retrofit optimization process (ROP, for currently manufactured systems). From the different groups within the Koppen-Geiger climate classification system, the ones in which the CPDEC had the potential of usage were identified; a sample city from each group was selected, and the features of the optimized systems for that condition were obtained. It was found that for all applicable climates in ROP as well as classes ‘B’ and ‘C’ in DOP, the optimum specific contact area was 540m2m−3. Moreover, the features of the optimized system in ROP were affected by both climatic and economic parameters while in DOP the effect of climatic condition was much more than economic criteria. The results also showed that in comparison to the base case conditions, MOOs improved, in average, LCC, AWC, and AACOP 52.8%, 74.3% and 146.9% in the case of DOP and 20.9%, 64.6% and 70.1% in the case of ROP. These mean significant improvements were achieved by MOOs in the both scenarios.