scholarly journals Impact of internal heat gain profiles on the design cooling capacity of landscaped offices

2021 ◽  
Vol 246 ◽  
pp. 07003
Author(s):  
Seyed Shahabaldin Seyed Salehi ◽  
Andrea Ferrantelli ◽  
Hans Kristjan Aljas ◽  
Jarek Kurnitski ◽  
Martin Thalfeldt
Keyword(s):  
Building Materials ◽  
Cooling System ◽  
Internal Heat ◽  
Cooling Capacity ◽  
Thermal Mass ◽  
Large Set ◽  
Cooling Systems ◽  
Heat Gain ◽  
Depth Analysis ◽  
The Impact

Using passive methods in façade design for controlling heating and cooling needs is an important prerequisite for constructing cost-effective nearly zero-energy buildings. Optimal control of solar heat gains reduces the cooling demand and the size of the active cooling systems. However, applying such methods increases the impact of internal heat gains on the heat balance of the buildings, and accordingly also the dimensions of cooling systems. Therefore, a good model of internal heat gains is needed for a reliable and optimal sizing of the cooling sources. This paper aims to bring understanding to developing internal heat gains models for sizing the cooling systems. For this purpose, several weekly internal heat gain profiles were selected from a large set of tenant-based electricity use measured in 4 office buildings in Tallinn. The selection was based on maximum daily or weekly peak loads of an office space per floor area. The selected profiles and the schedule of EN 16798-1 were used to dimension ideal coolers in the zones of a generic floor model with landscaped offices developed in IDA-ICE 4.8. The model had variable window sizes and thermal mass of the building materials. Finally, the internal heat gains models resulting in the largest cooling capacity were identified. We found that utilizing thermal mass can reduce the cooling system size by up to 7% on average and the models with big windows and light structure need the largest cooling systems. The cooling loads obtained with the profile of EN 16798-1 did not significantly differ from the average of other profiles’ results. This paper focused mainly on the zonal dimensioning of cooling systems, therefore a more in-depth analysis of the different occupancy patterns as well as developing models for dimensioning the cooling system at the building level, is needed.

Desiccant Degradation in Desiccant Cooling Systems: A System Study

1993 ◽  
Vol 115 (4) ◽  
pp. 237-240 ◽  
Author(s):  
A. A. Pesaran
Keyword(s):  
Cooling System ◽  
Cooling Capacity ◽  
Coefficient Of Performance ◽  
Thermal Coefficient ◽  
Ventilation Mode ◽  
Worst Case ◽  
Cooling Systems ◽  
Degradation Data ◽  
Percent Loss ◽  
The Impact

We predicted the impact of desiccant degradation on the performance of an open-cycle desiccant cooling system in ventilation mode using the degradation data on silica gel obtained from a previous study. The degradation data were based on thermal cycling desiccant samples and exposing them to ambient or contaminated air. Depending on the degree of desiccant degradation, the decrease in the thermal coefficient of performance (COP) and the cooling capacity of the system for low-temperature regeneration was 10 percent to 35 percent. The 35 percent loss occurred based on the worst-case desiccant degradation scenario. Under more realistic conditions the loss in system performance is expected to be lower.

Experimental Study of Capillary Radiant Cooling System with Parameters Changing

2013 ◽  
Vol 300-301 ◽  
pp. 1048-1053 ◽  
Author(s):  
Yong Hong Wang
Keyword(s):  
Room Temperature ◽  
Cooling System ◽  
Cooling Capacity ◽  
Test Methods ◽  
Radiation Response ◽  
Volume Changes ◽  
Indoor Temperature ◽  
Radiant Cooling ◽  
Radiation Laboratory ◽  
The Impact

In this paper, the test methods of radiation laboratory and data analysis in detail were introduced. The impact of the capillary system with different parameters changing, such as water temperature or water flow the capillary cooling capacity changes, and the capillary cooling system when the initial radiation response time were specificially studied. Under different parameters while cooling capillary volume changes associated with the indoor temperature can be seen under certain conditions, the capillary cooling capacity and room temperature has a linear relationship.

scholarly journals Energy Management Improving the Cooling System in a Local Factory

2019 ◽  
Vol 1 (4) ◽  
pp. 25-44
Author(s):  
ENG. Moath Abdrabu Eldbari ◽  
Muhammad N Radhwi
Keyword(s):  
Cooling System ◽  
Cooling Capacity ◽  
External Heat ◽  
Cooling Load ◽  
Total Rate ◽  
Gypsum Board ◽  
Heat Gain ◽  
The Third ◽  
Wool Material ◽  
Rock Wool

Development is an ongoing process in all areas and this research studied of a cooling system for a local factory and evaluated to determine the efficiency and capacity of the cooling capacity of the factory at the desired level. ِAfter evaluating the cooling system and studying the case of the local factory, the heat gain loads in the factory was calculated internally and externally and found that there is a deficit in the cooling system by 45% and the suggestion is to improve the cooling system without affecting production or manpower. Accordingly, three points have been developed to improve the cooling system and the first point is reducing the heat gained from lighting by changing fluorescent bulbs by the LED and this step will reduce the heat gain from lighting by 64%. The second point is to reduce the volume space of production zones by installing the ceiling of the gypsum board where the height was reduced from eight to five meters, which reduced the heat gained by 37% from the walls. The third point is the installation of better insulation materials and has been proposed rock wool material for the roof and the material Rigid expanded board for walls and these materials have reduced 85% of the heat gain from the roof and 20% of the walls. The total rate of improvement in the cooling system completely (internal and external heat gain) is 25% or in other words, can be through the implementation of these points reduce cooling load by 25%.

scholarly journals Experimental Study to Performance Improvement of Vapor Compression Cooling System Integrated Direct Evaporative Cooler and Condenser

2018 ◽  
Vol 215 ◽  
pp. 01017
Author(s):  
Arfidian Rachman ◽  
Lisa Nesti
Keyword(s):  
Energy Use ◽  
Cooling System ◽  
Electricity Consumption ◽  
Weather Condition ◽  
Heat Removal ◽  
Cooling Capacity ◽  
Cooling Power ◽  
Cooling Systems ◽  
Evaporative Cooler ◽  
And Performance

For areas with very hot and humid weather condition increased latent and sensible load are a major problem in cooling systems that will increase compressor work so that electricity consumption will also increase. Combined condenser with direct evaporate cooling will increase the heat removal process by using an evaporative cooler effect that will increase the efficiency of energy use. This paper presents the study of the use of evaporator cooling and condenser. This paper mainly calculated energy consumption in steam compression cooling systems and related problems. From the results of this study, the use of condensers with evaporative cooling, power consumption can be reduced to 46% and performance coefficient (COP) can be increased by about 12%, with 1,2 kW cooling capacity.

scholarly journals Innovative Turbine Intake Air Cooling Systems and Their Rational Designing

Energies ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 6201
Author(s):  
Andrii Radchenko ◽  
Eugeniy Trushliakov ◽  
Krzysztof Kosowski ◽  
Dariusz Mikielewicz ◽  
Mykola Radchenko
Keyword(s):  
Gas Turbines ◽  
Maximum Rate ◽  
Cooling System ◽  
Ambient Air ◽  
Cooling Capacity ◽  
Climatic Conditions ◽  
Air Cooling ◽  
Thermal Loads ◽  
Cooling Systems ◽  
Air Cooling System

The efficiency of cooling ambient air at the inlet of gas turbines in temperate climatic conditions was analyzed and reserves for its enhancing through deep cooling were revealed. A method of logical analysis of the actual operation efficiency of turbine intake air cooling systems in real varying environment, supplemented by the simplest numerical simulation was used to synthesize new solutions. As a result, a novel trend in engine intake air cooling to 7 or 10 °C in temperate climatic conditions by two-stage cooling in chillers of combined type, providing an annual fuel saving of practically 50%, surpasses its value gained due to traditional air cooling to about 15 °C in absorption lithium-bromide chiller of a simple cycle, and is proposed. On analyzing the actual efficiency of turbine intake air cooling system, the current changes in thermal loads on the system in response to varying ambient air parameters were taken into account and annual fuel reduction was considered to be a primary criterion, as an example. The improved methodology of the engine intake air cooling system designing based on the annual effect due to cooling was developed. It involves determining the optimal value of cooling capacity, providing the minimum system sizes at maximum rate of annual effect increment, and its rational value, providing a close to maximum annual effect without system oversizing at the second maximum rate of annual effect increment within the range beyond the first maximum rate. The rational value of design cooling capacity provides practically the maximum annual fuel saving but with the sizes of cooling systems reduced by 15 to 20% due to the correspondingly reduced design cooling capacity of the systems as compared with their values defined by traditional designing focused to cover current peaked short-term thermal loads. The optimal value of cooling capacity providing the minimum sizes of cooling system is very reasonable for applying the energy saving technologies, for instance, based on the thermal storage with accumulating excessive (not consumed) cooling capacities at lowered current thermal loads to cover the peak loads. The application of developed methodology enables revealing the thermal potential for enhancing the efficiency of any combustion engine (gas turbines and engines, internal combustion engines, etc.).

scholarly journals Effects of Cooling Systems on Greenhouse Microclimate and Cucumber Growth under Mediterranean Climatic Conditions

Agronomy ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 300 ◽  
Author(s):  
Georgios Nikolaou ◽  
Damianos Neocleous ◽  
Nikolaos Katsoulas ◽  
Constantinos Kittas
Keyword(s):  
Vapor Pressure Deficit ◽  
Cooling System ◽  
Ventilation System ◽  
Climatic Conditions ◽  
Irrigation Regime ◽  
Crop Water ◽  
Water Losses ◽  
Cooling Systems ◽  
Cropping Seasons ◽  
The Impact

Two experiments were conducted in different cropping seasons under Mediterranean climatic conditions to investigate the impact of two cooling systems (fan-pad evaporative as opposed to fan ventilation) on greenhouse microclimate and soilless cucumber growth. The second objective of the experiment was to determine the most appropriate irrigation regime (between 0.24 and 0.32 L m−2) in relation to crop water uptake and greenhouse fertigation effluents. The use of a fan ventilation system enhanced the vapor pressure deficit; thus, the crop transpiration improved by 60% in relation to the transpiration rates of plants grown under the fan-pad system. Higher transpiration rates alleviated the heat load as the external–inside greenhouse air differences declined from 6.2 °C to 3 °C. The leaf–air temperature differential indicated that plants were not facing any water stress conditions for both cooling systems tested; however, fan ventilation reduced drainage emissions outflows (95% decrease) compared with evaporative cooling. Results also demonstrated that an irrigation regime of 0.24 L m−2 can be applied successfully in soilless cucumber crops, keeping the drainage to a minimum (20% of the nutrient solution supply). These results suggest that fan ventilation cooling system in conjugation with an appropriate irrigation regime prevents overheating and minimizes the nutrient and water losses in spring-grown soilless cucumber crops in Mediterranean greenhouses without compromising yield.

The impact of thermal mass on cold and hot climate zones of Portugal

2016 ◽  
Vol 26 (6) ◽  
pp. 733-743 ◽  
Author(s):  
Jorge S. Carlos
Keyword(s):  
Heat Capacity ◽  
Thermal Resistance ◽  
Energy Demand ◽  
Dynamic Modelling ◽  
Internal Heat ◽  
Energy Performance ◽  
Thermal Mass ◽  
Steady State Condition ◽  
Climate Conditions ◽  
The Impact

The aim of this paper is focused on the energy performance of buildings containing massive wall alternatives. The analysis comprised the comparison of the heating and cooling loads of seven characteristic wall configurations of one sample building with different dynamic internal heat capacity (ISO 13790:2008) in spite of the equal thermal resistance. The equal thermal resistance, as derived from simple steady-state condition, was imposed in order to allow research of effects solely attributed to the wall heat capacity on the building performance. A detached one floor dwelling exposed to different climate conditions in Portugal was analysed to illustrate the effect of the same wall in terms of energy demand during cold and hot weather conditions. A whole building dynamic modelling using EnergyPlus was employed for the energy analysis. The best thermal performance was obtained with massive walls that were located at the inner side, for a very heavy weight building and high building time constant.

Facility Cooling Failure Analysis of Direct Liquid Cooling System in Data Centers

2018 ◽  
Author(s):  
Sami Alkharabsheh ◽  
Udaya L. N. Puvvadi ◽  
Bharath Ramakrishnan ◽  
Kanad Ghose ◽  
Bahgat Sammakia
Keyword(s):  
Data Center ◽  
Cooling System ◽  
Rate Of Change ◽  
Operating Conditions ◽  
Thermal Mass ◽  
Liquid Cooling ◽  
Chip Temperature ◽  
Fan Speed ◽  
Liquid Cooling System ◽  
The Impact

This work experimentally studies the impact of facility cooling failure of a direct liquid cooling (DLC) system on the IT equipment (ITE). The facility side of a DLC system removes the heat from a secondary loop — in direct contact with the ITE — and discard it in a chiller loop or ambient. The CPU utilization and coolant set point temperature (SPT) are varied to understand the effect of failure under different operating conditions. The ITE response is studied in terms of chip temperature and power, and fan speed. It was found that failure of the facility cooling system is not hazardous to the IT operation. The rate of change in temperature after failure is low and is sufficient to turn the ITE off safely. This is attributed to the surrounding air in the data center and the thermal mass of the cooling system.

scholarly journals The Impact of Occupancy-Driven Models on Cooling Systems in Commercial Buildings

Energies ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1722
Author(s):  
Seyyed Danial Nazemi ◽  
Esmat Zaidan ◽  
Mohsen A. Jafari
Keyword(s):  
Energy Consumption ◽  
Optimization Algorithm ◽  
Cooling System ◽  
Linear Optimization ◽  
Electricity Consumption ◽  
Commercial Buildings ◽  
Optimization Approach ◽  
Cooling Systems ◽  
Rule Based ◽  
The Impact

Cooling systems play a key role in maintaining human comfort inside buildings. The key challenges that are facing conventional cooling systems are the rapid growth of total cooling energy and annual electricity consumption in commercial buildings. This is even more significant in countries with an arid climate, where the cooling systems are typically working 80% of the year. Thus, there has been growing interest in developing smart control models to assign optimal cooling setpoints in recent years. In the present work, we propose an occupancy-based control model that is based on a non-linear optimization algorithm to efficiently reduce energy consumption and costs. The model utilizes a Monte-Carlo method to determine the approximate occupancy schedule for building thermal zones. We compare our proposed model to three different strategies, namely: always-on thermostat, schedule-based model, and a rule-based occupancy-driven model. Unlike these three rule-based algorithms, the proposed optimization approach is a white-box model that considers the thermodynamic relationships in the cooling system to find the optimal cooling setpoints. For comparison, different case studies in five cities around the world were investigated. Our findings illustrate that the proposed optimization algorithm is able to noticeably reduce the cooling energy consumption of the buildings. Significantly, in cities that were located in severe hot regions, such as Doha and Phoenix, cooling energy consumption can be reduced by 14.71% and 15.19%, respectively.

scholarly journals Effect of Climate Change and Occupant Behaviour on the Environmental Impact of the Heating and Cooling Systems of a Real Apartment. A Parametric Study through Life Cycle Assessment

Energies ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 8356
Author(s):  
Gianmarco Fajilla ◽  
Emiliano Borri ◽  
Marilena De Simone ◽  
Luisa F. Cabeza ◽  
Luís Bragança
Keyword(s):  
Climate Change ◽  
Life Cycle Assessment ◽  
Life Cycle ◽  
Energy Consumption ◽  
Environmental Impact ◽  
Cooling System ◽  
Occupant Behaviour ◽  
Cooling Systems ◽  
Heating And Cooling ◽  
The Impact

Climate change has a strong influence on the energy consumption of buildings, affecting both the heating and cooling demand in the actual and future scenario. In this paper, a life cycle assessment (LCA) was performed to evaluate the influence of both the occupant behaviour and the climate change on the environmental impact of the heating and cooling systems of an apartment located in southern Italy. The analysis was conducted using IPCC GWP and ReCiPe indicators as well as the Ecoinvent database. The influence of occupant behaviour was included in the analysis considering different usage profiles during the operational phase, while the effect of climate change was considered by varying the weather file every thirty years. The adoption of the real usage profiles showed that the impact of the systems was highly influenced by the occupant behaviour. In particular, the environmental impact of the heating system appeared more influenced by the operation hours, while that of the cooling system was more affected by the natural ventilation schedules. Furthermore, the influence of climate change demonstrated that more attention has to be dedicated to the cooling demand that in the future years will play an ever-greater role in the energy consumption of buildings.

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