Tank Size Research Articles

Assessment of Rainwater Harvesting Facilities Tank Size Based on a Daily Water Balance Model: The Case of Korea

Factors affecting rainwater resource management for the present and future include population growth, urbanization, and climate change. Rainwater harvesting (RWH) allows multiple urban water-related issues to be mitigated. In this study, a spreadsheet-based daily water balance model was developed to analyze the existing laws and regulations regarding the storage tank size of RWH facilities. Six buildings at different locations were selected for this study. Two are office buildings, two are school buildings, and two are sports buildings. The term “RWH facility evaluation criteria” is collectively used for rainwater supply satisfaction rate, rainwater guarantee rate, and rainwater utilization rate. A green roof can hold the rainwater for some time, reducing the peak flow and runoff volume. The results provide evidence that, among the selected studied buildings, buildings having a combination of a green roof and RWH facility score the highest in terms of RWH facility evaluation criteria, even though the actual tank size is much smaller than the standard tank size. This is the case with the Yesan County Office, in which a green roof connected to a small (66 m3) rainwater storage tank is installed. As a green roof can decrease the runoff volume, the rainwater can be managed efficiently with less pumping energy and only a small storage tank.

Optimization of collector area and storage volume in domestic solar water heating systems with on–off control—A thermal energy analysis based on a pre-specified system performance

Numerical simulations of solar water heating systems using on–off control were performed for four locations in the Portuguese territory, two collector types, and a wide range of parameters. Two main design parameters were considered: the collector area and the storage volume. An innovative technique was used to investigate the relationship between system performance and system parameters: a pre-specified annual solar fraction is selected and the optimal parameters needed to achieve this solar fraction are then computed. The optimum collector area is almost always higher for a double-glazed than for a single-glazed collector, suggesting that in Portugal, the single-glazed type is more effective for most solar water heating applications. This fact is more significant for lower solar fractions and warmer climates. A small increase in the optimum collector area leads to a very strong decrease in the optimum storage volume (an area increase of 1% leads to a volume decrease of 27%). Collector flow rate and storage volume increments result in lower collector areas. However, high flow rates lead to high pumping losses and lower collector efficiencies, and when the storage tank losses are significant, higher tank sizes may lead to higher collector areas. The solar fraction has a very strong impact on the collector area and storage volume (when the solar fraction increases from 0.5 to 0.99, the optimum collector area and storage volume increase about 17 and 56 times, respectively).

Implementing rainwater harvesting systems as a novel approach for saving water and energy in flat urban areas

Implementation of rainwater harvesting systems (RHS) is an effective approach to tackle increasing water and energy shortages for sustainable urban development. However, water and energy saving executions of RHS are rarely explored together in cities. This study explores the water and energy saving and economic performances of RHS in the four cities (Islamabad, Lahore, Peshawar, and Khanpur) under different climate zones of Pakistan. Three water demands (lawn irrigation, toilet flushing, and their mixture) were evaluated. Results indicated that higher annual water savings of RHS were associated with larger tank-sizes and lesser water demands in humid region. Differently, higher annual energy savings of RHS were related to greater energy consumption for groundwater pumping and larger tank sizes. At Islamabad, a 20 m3 RHS can achieve 126 m3 of annual water savings and 80% time reliability for mixed water demand, but only 23 m3 of annual water savings and 10% time reliability at Khanpur. At Lahore, a 20 m3 RHS can attain 119 kWh of annual energy savings for mixed water demand, but only 20 kWh at Khanpur. The economic viability of RHS was confirmed through adequately designed RHS at Islamabad, Lahore, and Peshawar, but except Khanpur due to its lower benefit-cost-ratio than 1.0.

Optimal sizing of rainwater harvesting tanks for domestic use

La captación de agua de lluvia es una alternativa que puede contribuir a la solución de los problemas de escasez de agua. Sin embargo, debido a que en el diseño de un sistema de captación de agua de lluvia (SCALL) influyen diversas variables, la selección correcta de la capacidad adecuada del tanque de almacenamiento puede ser una tarea difícil para las personas que no cuentan con conocimientos hidrológicos básicos, como los propietarios de una casa o los miembros de alguna organización no gubernamental. El objetivo de este estudio fue desarrollar modelos regionales para estimar el volumen óptimo de tanques de recolección de agua de lluvia en comunidades de la Cuenca Alta del Río Mixteco (CARM) en Oaxaca, México. Con base en el análisis de datos diarios de lluvia de 12 estaciones climatológicas y la aplicación del método de balance de agua se realizaron simulaciones del funcionamiento de tanques de distintas capacidades para distintos números de usuarios, superficies de captación y fracciones de demanda. Como resultado se obtuvo la variación espacial de las capacidades óptimas de tanques que, junto con datos de lluvia media anual, se utilizaron para la obtención de ecuaciones de regresión exponencial. Se determinó que las capacidades de los tanques serán mayores en localidades del norte de la cuenca donde llueve menos; mientras que hacia el suroeste se requieren tanques de menor capacidad. Por otro lado, los modelos regionales permitirán cuantificar de manera práctica la capacidad del tanque para el diseño funcional de los SCALL en la CARM.

Rainwater Harvesting for Urban Landscape Irrigation Using a Soil Water Depletion Algorithm Conditional on Daily Precipitation

The supply of various non-potable water usages based on the harvesting and management of rainwater in urban areas allows to save high-quality water resources for strictly potable use and to limit the squandering of precious freshwater resources. A rainwater harvesting system included in a reconversion project of a former military area located in the town of Genova (Italy) is examined. Rainwater is collected and used for the landscape irrigation of public areas. Three rainwater collection scenarios are considered while varying the size of the storage tank, using daily rainfall data from a local long-term record as the reference rainfall climatology. A behavioural model is adopted to simulate the operation of the rainwater harvesting system and improved with a dedicated algorithm to account for the actual soil water availability for the vegetation and its temporal decay, based on the specific soil type and vegetation. For each scenario/tank size combination, reliability indices are calculated and compared, while the detention time and the annual usage volume per unit tank capacity are used as indicators of water quality deterioration in the tank and the economic benefit associated with the exploitation of the resource. The best solution in terms of rainwater collection scenario and tank size is identified.

Influence of the Temporal and Spatial Variability of Rainfall on the Sizing of Tanks for Rainwater Harvesting in Brazil: A Multivariate Analysis

Influence of the Temporal and Spatial Variability of Rainfall on the Sizing of Tanks for Rainwater Harvesting in Brazil: A Multivariate Analysis

CFD assessment of the wind forces and moments of superstructures through RANS

In addition to wind tunnel tests and regression formulae, numerical simulation has begun to be used at the design stage of ships as a method for estimating the wind force and moments of superstructures. However, no specific approach has been proposed to verify the grid dependence around superstructures, and the degree to which differences in computational conditions affect the results has not yet been systematically clarified. Therefore, a new approach to grid sensitivity analysis is carried out. The effect of some computational conditions on the computed result is investigated using an in-house solver with an overset grid technique with a Japan Bulk Carrier(JBC) model. The method that verifies the grid sensitivity of the hull and the superstructures separately can obtain equivalent results to the method of simultaneously verifying both of them. The grid sensitivity analysis of the superstructures can be performed separately from the hull. The comprehensive comparative study reveals five findings: the blockage effect of the tank size is slight, the steady-state computation is capable of estimating as well as unsteady computation, wall function can be applied to object surfaces, a difference of wind profiles of incident flow can be recovered by the normalization based on the momentum integration in a shear flow, and the Reynolds number effect does not need to be considered if it is greater then 1.0×106. The computations for other ship types are also performed. The computed results show good agreement with the measured data, while the regression formula shows differences from the measured data in some cases. The above study has shown that steady-state CFD analysis is capable and viable in estimating the wind forces and moments of superstructures of a ship model in a wind tunnel for various ship types.

Development and validation of Nusselt number correlations for a helical coil based energy storage integrated with solar water heating system

Storage tanks based on helical coil heat exchangers are an integral part of solar water heating systems and require optimal design configuration to achieve maximum heat transfer and a longer storage period. This study is focused on thermal analysis of a vertical helical coil-based water storage tank and derivation of inner and outer Nusselt number correlations by considering the storage tank as well as helical coil and catering to both forced and natural convection effects. A fluid-fluid conjugate heat transfer transient state model is validated with experiments performed with 50/50 % water-glycol mixture as heat transfer fluid at flow rates of 2 and 3 L/min in a solar water heating system, while water remains at static flow condition inside the tank. To reduce the computational cost, a symmetrical downsized (50 % of the real storage tank size) model is also designed and validated, which showed a mean absolute percentage error of 3.25 %. In order to derive the mathematical correlations, alterations were made to the validated model by using coils with curvature ratios ranging from 0.09 to 0.184 with HTF flow rates in laminar flow regimes, ranging from 30 to 100 L h−1 at temperatures from 40 °C to 80 °C. Furthermore, inner Nusselt number mathematical correlations based on M number, curvature ratio, and Prandtl number showed good agreement with correlations derived by past investigators. Similarly, the outer Nusselt number of the coil was related to Rayleigh's number and the derived relations showed good agreement with the past studies, while Nuo = 0.1996 (Rado0.326) showed the least error of 2.06 %. Finally, thermal stratification analysis helped to understand that coil position and aspect ratio determine the thermocline developed inside the storage tank. Results show that extension of coil inside the tank up to 83.7 % of the tank height, ensured greater thermocline range, and tank with aspect ratio 3 turned to be better for thermal energy storage for longer period.

The effect of fish density and tank size on the behavior of adult zebrafish: A systematic analysis.

The zebrafish has been employed in several fields of biology due to its translational relevance and its simplicity and ease of maintenance. As a result, zebrafish are kept in thousands of laboratories around the world. Current industry standards favor keeping the largest possible number of fish in the smallest possible volume of water to increase efficiency and reduce costs. However, physiological and psychological stress resulting from such crowding may impact a variety of phenotypes, from brain function and behavior to cardiovascular function and cancer. Nevertheless, surprisingly little is known about what constitutes an optimal housing environment for the zebrafish, e.g., no systematic analyses have been performed to test the role of housing density and tank volume despite recent sporadic reports implying negative effects of the standard practice of crowding. Here, we conduct the first proof of concept analysis examining the potential impact of housing density and tank volume on the behavior of zebrafish. We randomly assigned adult zebrafish to one of three tank sizes (1.5, 10, or 50 L) with one of three housing densities (1, 2, or 4 fish/L), a 3 × 3 between subject experimental design, and maintained the fish in their corresponding condition for 2 weeks. Subsequently, we tested the behavior of the fish singly in a novel open tank for 12 min and quantified several of their swim path parameters using a video-tracking system. We found significant additive and interacting effects of tank size and/or housing density on swim path parameters including immobility, swim speed, turn angle, and distance to bottom and to stimulus. Although we had only three fish densities and three tank sizes and we did not explore the effects of more extreme conditions and although the interpretation of the above behavioral effects is speculative at this point, the results already demonstrate that both tank size and housing density exerts significant effects on the zebrafish and thus should be considered in zebrafish husbandry.

Assessing the Impacts of Climate Change on Rainwater Harvesting: A Case Study for Eight Australian Capital Cities

Due to climate change, freshwater supply will be limited at many locations around the globe. Rainwater harvesting (RWH) has emerged as an alternative and sustainable freshwater source. In this study, the impacts of climate change on water saving as well as the reliability of a RWH system are investigated using data from eight Australian capital cities. Both historical and projected rainfall data were incorporated into a daily water balance model to evaluate the performance of a RWH system in relation to its reliability, water savings and scarcity. Indoor (toilet and laundry), outdoor (irrigation) and combined (indoor plus outdoor) water demands were considered for a 5 m3 tank size. It has been found that in the future period, the water savings and reliability of a RWH system will reduce slightly across the selected cities. Different capital cities of Australia will experience different level of performance for a RWH system depending on their locations, water uses and seasons. The findings of this study will be useful to water authorities and policy makers to plan for a sustainable RWH system under changing climate conditions.

New modelling approach to optimize rainwater harvesting system for non-potable uses and groundwater recharge: A case study from Israel

• A rainwater harvesting system from a building in Israel was used as a case study. • Precipitation, runoff coefficient and non-potable consumption were measured. • Measured data used to model and assess the efficiency of the system. • Results are stochastic, allowing to assess variability of the system performance. Countries with dry climates must optimize the use of natural water sources. Rainwater Harvesting (RWH) is a viable water source for non-potable uses. Besides, rainwater can also be used for managed aquifer recharge (MAR). This work discusses the combined use of RWH for toilet flushing and MAR. A mass-balance simulation was used to estimate efficiency of the combined system in a building in Israel equipped with a RWH system used for MAR only. This enabled the use of actual water consumption patterns and the development of a runoff function using rainfall and runoff measurements. By the novel use and the integration of measured dynamic data into the model, the results are stochastic and the variability and uncertainty of the performance of the RWH system could be assessed. Non-potable water savings were ∼20% for the expected cost-effective tank size, and in this case ∼40% of the rainwater was used for MAR. The stochastic approach of the combined system proved the importance of the non-potable consumption value as well as precipitation series. Finally, it is shown that the potable water savings from using rainwater for toilet flushing would represent an annual CO 2 emissions reduction of 267 kg.

Improvement of Gas–Liquid Separation Performance of Engine Oil Using Swirling

The purpose of this study is to improve the gas–liquid separation performance of an oil tank and to establish a design method to enable gas–liquid separation only in an oil tank. Since it is difficult for conventional oil tanks to completely remove bubbles remaining in the hydraulic oil, it is essential to introduce a technology to actively separate and remove bubbles from the oil. Therefore, the bubble removal performance was improved even under the condition of added lateral acceleration by appropriately generating a swirl flow. First, an acrylic model of an oil tank was used to verify the accuracy by performing numerical analysis using various turbulence models. Then, the parameters of the bubble remover, such as the size of the oil tank, were studied. In addition, the bubble removal performance under the condition of added lateral acceleration was examined.

Techno-Economic Analysis of dual ejectors solar assisted combined absorption cooling cycle

This paper deals with the Techno-Economic Analysis of dual ejectors –flash tank absorption cooling cycle assisted by solar energy. In this study, the solar system is simulated using the TRNSYS software and a one-dimensional ejector is modeled in EES (Engineering Equation Solver) using NH3/H2O as working fluids. A cooling capacity of 5 kW is considered and a parametric optimization is carried out to select the optimum size of the thermal solar system. The design of the absorption cooling cycle under the Malaysia climate conditions was 5 kW (about 1.5 refrigeration ton) with a solar thermal collector (evacuated tube solar collector of 8.5 m2 sloped at 14° and 0.35 m3 tank size with 0.1 kg s−1 for fluid flow rate). The solar fraction varied between 53.6% in March and 68.6% in February. The payback period and profit gain for the dual ejector cycle, flash –tank with ejector and basic cycle with only ejector are 11 yr, 3192 $; 13.5yr, 1647$; and 16 yr, 874$ respectively. The results also show that the combined dual ejectors-flash tank cycle (Cycle 3) was up to 27% less than of the absorption combined ejector system (Cycle -1), and 10% cheaper than the combined ejector –flash tank absorption system (Cycle -2). Therefore, the economic analysis showed that the absorption system with dual ejectors (Cycle -3) was the preferred option.

Influence of rainfall time series indicators on the performance of residential rainwater harvesting systems

Despite having abundant water sources, some Brazilian regions are likely to face water scarcity within the following decades. In this sense, rainwater harvesting (RWH) systems are considered viable solutions. This study evaluates the influence of rainfall time series indicators on the tank sizes, volumetric reliability and potential for potable water savings in residential buildings in Brazil. The study aimed to determine the most suitable rainfall conditions for RWH systems design. RWH systems were simulated for 27 Brazilian cities considering a daily water balance model. Total water demands and rainfall time series were considered for each city, and RWH-relevant indicators characterised each time series. Generally, cities with higher rainfall availability required smaller tank sizes and yielded greater volumetric reliabilities and potential for potable water savings. Cluster analysis was also used to investigate if similar rainfall patterns generate similar simulation results. Euclidean distance criteria grouped similar time series into ten clustering schemes. Coefficients of variation for tank sizes decreased within each scenario as more clusters were used, i.e. this method is feasible to design rainwater storage tanks. The remaining performance indicators did not show significant variation among the tested clustering scenarios. Similarity analysis resulted in increasingly similar results within each group as the clustering became more refined. As the main conclusion, correlation analysis presented the Seasonality index and indicators related to dry periods as the most influential towards the performance of RWH systems.

Influence of the water tank size and air source heat pump size on the energy saving potential of the energy storage heating system

“Clean heating” has become a national strategy for energy conservation and carbon reduction in China. The energy storage heating system with air source heat pump and water tank has been proven to be energy saving in the previous studies. However, how to determine the sizes of the water storage tank and the air source heat pump based on the building heating load profile has not been investigated comprehensively. In this paper, the model of the energy storage heating system is established on the TRNSYS platform and validated by long-term monitored data. The influence of the water storage tank size and the air source heat pump size on the energy saving potential of the energy storage heating system is investigated comprehensively. The results show that even a small water tank, i.e., 0.06 m3 ~ 0.5 m3, can reduce the start-stop loss of the air source heat pump effectively. When the water tank volume increases to 0.5 m3 and 1 m3, the start-stop loss is reduced from 12.5 % to 0.8 % and 0.2 %, respectively. When the water tank volume increases from 1 m3 to 4m3, the average operating temperature difference of the air source heat pump between the energy storage heating system and the baseline heating system increases from 0.7 to 3.3 °C, and the corresponding energy saving rates caused by the operating temperature difference is approximately 1.0 % ~ 6.3 %. When the ASHP size varies from 80 % to 100 % of the design heating load of the building, the energy saving rates change within 1 %. The ASHP size can be reduced to a certain extent to reduce the investment of the energy storage heating system.

Assessment of hydrogen fuel for rotorcraft applications

This paper presents the application of a multidisciplinary approach for the preliminary design and evaluation of the potential improvements in performance and environmental impact through the utilization of compressed (CGH2) and liquefied (LH2) hydrogen fuel for a civil tilt-rotor modelled after the NASA XV-15. The methodology deployed comprises models for rotorcraft flight dynamics, engine performance, flight path analysis, hydrogen tank and thermal management system sizing. Trade-offs between gravimetric efficiency, energy consumption, fuel burn, CO2 emissions, and cost are quantified and compared to the kerosene-fuelled rotorcraft. The analysis carried out suggests that for these vehicle scales, gravimetric efficiencies of the order of 13% and 30% can be attained for compressed and liquid hydrogen storage, respectively leading to reduced range capability relative to the baseline tilt-rotor by at least 40%. At mission level, it is shown that the hydrogen-fuelled configurations result in increased energy consumption by at least 12% (LH2) and 5% (CGH2) but at the same time, significantly reduced life-cycle carbon emissions compared to the kerosene counterpart. Although LH2 storage at cryogenic conditions has a higher gravimetric efficiency than CGH2 (at 700 bar), it is shown that for this class of rotorcraft, the latter is more energy efficient when the thermal management system for fuel pressurization and heating prior to combustion is accounted for.

Investigating the hybridisation of micro-scale concentrated solar trigeneration systems and wind turbines for residential applications using a dynamic model

Solar and wind energy sources are envisioned to play a key role in the transition towards fully renewable energy systems but both suffer from their intermittent nature, which can be relieved by hybridisation. Hence, the benefits of the complementarity of these sources are investigated hereunder by considering a small-scale hybrid trigenerative system consisting of a Linear Fresnel Reflector solar field with a 440 m2 collector area, a 20 kWe/100 kWt organic Rankine cycle unit combined with a latent heat thermal energy storage system, an absorption chiller, and a 20 kWe wind turbine for the provision of electricity, heating and cooling to 10 residential apartments. To this end, a dynamic model and suitable control logic are developed to assess and compare the performances of the proposed hybrid system concerning the solar plant and wind turbine separately.The results show that hybridisation can extend the annual thermal coverage by renewables by 3.7–6.1% for the investigated locations by increasing the operation of the organic Rankine cycle unit, especially in winter. In particular, the surplus electrical energy from the wind turbine is used to satisfy 6% and 4% more than the separate configuration of the annual thermal and electrical demands for Ancona. As a result of hybridisation, the annual thermal energy consumption of the boiler reduces by 8.3%, 9.9%, and 37.6% for Perugia, Ancona, and Messina respectively, which shows the impact of the profile of the energy sources. At the same time, hybridisation improves grid stability by reducing the excess electricity production 18.2%, 19.2%, and 26.3% for Perugia, Ancona, and Messina respectively.A sensitivity analysis for Ancona has revealed that the size of the water thermal energy storage tank does not have a significant impact on the electrical and thermal coverage of the hybrid system, while electrical and thermal coverages improve 11.1% and 6.7% respectively by doubling the wind turbine capacity along with a 14.8% drop in the thermal energy consumption by the boiler. In brief, the analysis has shown the complementarity of these energy sources and the benefits of hybridisation for trigenerative systems for residential buildings.

A Preliminary CFD and Tritium Transport Analysis for ARC Blanket

The Affordable, Robust, Compact (ARC) fusion reactor is a preconceptual design proposed by the Plasma Science and Fusion Center at the Massachusetts Institute of Technology that will be developed by Commonwealth Fusion Systems. ARC features a Li2BeF4 (FLiBe) molten salt liquid blanket that provides reactor cooling, neutron shielding, and tritium breeding. This work aims to develop a preliminary coupled computational fluid dynamics (CFD) and tritium transport model to describe FLiBe flow inside the tank and to assess ARC tritium inventory in the vacuum vessel and blanket. Both models are built by taking advantage of COMSOL® Multiphysics. FLiBe velocity and temperature fields are evaluated by the CFD models, and they are passed as input to the tritium transport model. The tritium transport model computes tritium concentration inside solid materials and FLiBe. An auxiliary FLiBe inlet has been moved from the original position in the ARC preconceptual design to improve blanket cooling and to reduce the size of flow eddies. Results show that many recirculation zones generate inside the tank for the chosen tank geometry, size, and inlet-outlet conditions. Larger FLiBe temperature and tritium concentration are found in these zones. The high FLiBe temperature in recirculation areas may not allow for effective cooling, and Inconel 718 reaches critical temperatures. The largest tritium concentration for a steady-state model with continuity of tritium partial pressure at the interfaces is found in Inconel 718 while the second-highest concentration is reached in FLiBe. The total tritium inventory in the ARC blanket with the assumed model is quantified as 3.16 g.

Enhanced photovoltaic efficiency through radiative cooling augmented by a thermosyphon effect

A passive radiative cooling system that can produce cold water at night and act as an active cooling channel during the daytime is proposed to enhance the photovoltaic efficiency of a conventional PV module. At night, the PV module acts as a radiative cooling surface on which cold energy can be harnessed by passing water underneath the PV module. We show that a thermosyphon effect can circulate water in a closed-loop at night without any power consumption. On the other hand, the stored cold water can be fed through the water channel and cool the PV module during the daytime. A quasi-steady-state one-dimensional simulation code has been developed to analyze the annual performance of the proposed radiative-cooling-assisted PV module system. In this study, we have taken into account two parameters: the water mass (or water storage tank size), which ranges from 100 to 700 kg, and the insulation covering the storage tank, which ranges from no insulation to perfect insulation. By taking the total amount of water as the main design parameter of the proposed system, we show that it is beneficial to install a tank to hold more than 300 kg. Moreover, no insulation on the storage tank is found to be desirable for further enhancing the photovoltaic efficiency. It is also revealed that the efficiency enhancement is closely related to the climate conditions, in particular, the diurnal temperature range. Thorough analysis indicates that the proposed system is appropriate for hot, dry locations where the diurnal temperature range is relatively large. For example, the proposed system can enhance the net power output by 6.4% as compared to a conventional PV module in Phoenix. We think that the proposed radiative cooling system will be a great way to make conventional PV modules work more efficiently.

Thermal‐hydraulic investigation of a proposed concept for a passive containment cooling system and evaluation of heat exchanger performance

Reduction in ambient pressure within the containment of a light water reactor in the event of a hypothetical Loss of Coolant Accident (LOCA) is crucial for containment integrity. This article introduces the distinct concept of a Passive Containment Cooling System (PCCS). In the proposed PCCS concept, the containment is divided into two compartments with appropriate volumes. An external heat exchanger is connected between the two compartments of the containment for heat transfer and pressure reduction in the case of LOCA. This concept has unique characteristics and provides many advantages over previous designs. A RELAP5 model was developed to perform thermal-hydraulic analysis of the proposed PCCS concept. The performance of the PCCS after its deployment on a small reactor (998.6 MWth) has been assessed under various conditions following LOCA. The results indicate that partitioning of the containment creates a differential pressure that acts as a driving force for flow through the PCCS heat exchanger. Consequently, a decrease in long-term containment pressure is observed. In the case of equal volume fractions in the two containment compartments, the PCCS reduces long-term pressure in the containment by 16.5%. Sensitivity analysis was conducted in which the flow area of the PCCS inlet line, the heat transfer area, and the size of the heat exchanger tank were varied. The PCCS heat transfer capacity increases as these parameters are increased. However, the former is less sensitive than the latter two. The performance of the PCCS heat exchanger under steady-state conditions was validated using RELAP5 simulations, empirical correlations, and analytical models. The evaluation of heat exchanger parameters by various methods (presented in Appendix 1 ) was found in close agreement.