Heating and cooling systems Research Papers (original) (raw)

Degree days represent a versatile climatic indicator which is commonly used in building energy performance analysis.
In this context, the present paper proposes a simple dynamic model to simulate heating/cooling energy consumption in
buildings. The model consists of several transient energy balance equations for external walls and internal air according to a lumped-capacitance approach and it has been implemented utilizing the Matlab/Simulink® platform. Results are validated by comparison to the outcomes of leading software packages, TRNSYS and Energy Plus.
By using the above mentioned model, energy consumption for heating/cooling is analyzed in different locations, showing that for low degree days the inertia effect assumes a paramount importance, affecting the common linear behavior of the building consumption against the standard degree days, especially for cooling energy demand.
Cooling energy demand at low cooling degree days (CDD) is deeply analyzed, highlighting that in this situation other
factors, such as solar irradiation, have an important role. To take into account these effects, a correction to CDD is proposed, demonstrating that by considering all the contributions the linear relationship between energy consumption and degree days is maintained.

- by and +1
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- Sustainable Building Design, Built Environment, Heating and cooling systems, HVAC and Sustainability

Nowadays, considering the importance of the energy issue, it has become a major concern of economic topic. According to the energy balance sheet data, more than one third of the total energy consumption in Iran is consumed in the building sector. With regard to the massive waste of energy in the existing buildings, as well as the low efficiency of heating and cooling systems, seeking the right solution to reduce energy consumption in this sector is of utmost important. In this study, based on mathematical modeling, a solution has been presented to help us choose a proper combination of primary building materials and active or inactive air conditioning systems for residential buildings. It aimed to minimize both costs and thermal energy consumption of building materials. The proposed model has been utilized for a residential building in Tehran. Then, the optimal combinations of materials have been determined based on national building regulations (code 19).

Cooling System
Secondary Cooling System
Cooling Tower
Soğutma Sistemi

- by Ahmet Oven
- •
- Engineering, Mechanical Engineering, Heating and cooling systems, Enerji

While solar energy can be utilized for passive space heating, efficient passive space cooling is achievable through lower temperature ambient thermal sources. In this study, a model was proposed for the combined solar heating and radiative cooling and a MATLAB code is developed to simulate combined space heating and cooling of a small building in Louisville, Kentucky. The combined system consists of the glazing/transparent insulation subsystem and the thermal storage subsystem. The space is passively heated and cooled by means of natural convection from the surfaces of the storage subsystem where the storage tank is heated by solar radiation and cooled by night sky radiation as a low temperature thermal source. The model for this system consists of several transient energy balance equations based on the lumped capacitance approach and it has been implemented utilizing MATLAB. Using the aforementioned system and the auxiliary heating/cooling units, the room temperature can be kept within the prescribed comfort range. The simulation is carried out to find the monthly and annual solar fraction, required heating demand, auxiliary heating demand as well as the unwanted heat gain during heating months. Also, the radiative cooling fraction, required cooling demand and auxiliary cooling demand during cooling months are obtained. The optimum value for transparent layer absorptivity was found to avoid unwanted heat gain. Parametric sensitivity was evaluated for material and design features related to the combined system. Simulation results for temperature profiles of the room and storage tank are also illustrated.

Roman baths were a place of innovation and ingenuity, where new technology and architectural elements were invented and implemented. The Stabian Baths at Pompeii are one of the earliest Roman bath complexes to have been discovered thus far. They were transformed from a rudimentary space heated by braziers to an elaborate complex with subfloor and intramural heating systems that influenced other structures in Pompeii and throughout the Roman world. This paper presents preliminary annual fuel consumption values for the Stabian Baths and compares them to other bath buildings. The structure and heating systems of the Stabian Baths are described and evaluated in terms of their efficiency. The Stabian Baths contained both tubuli and tegulae mammatae, which were used to heat the walls of the baths. This arrangement is very unusual, and it is unlikely that these devices could have worked symbiotically. Rather, one device was probably being replaced by the other in the post-AD 62 earthquake reconstructions that the bath was still undergoing at the time of the eruption. The structure is evaluated with both of these elements present and in its current state. Computing fuel quantities under different scenarios reveals how different structural elements and operational choices affected consumption. Modeling these values over the course of a month and a year provides quantitative data that can be used in further studies related to deforestation and environmental impact, the transport and storage of resources to and within the city, along with the cost of maintaining such a facility.

The conventional mechanical building cooling systems are energy demanding equipment. Needing for low-energy consumption systems is a motivation for utilizing ambient energy resources such as ground, ambient air, sky and water as alternative resources. Night sky can be a good candidate as a heat sink to be used in cooling systems. The present study proposes and presents a simplified method for computing net outgoing energy exchanged between night sky and a cool-pool in a building cooling system. Considering a real night condition with a 3m × 4m pool and overall energy conversion efficiency of 75%, we obtained that the aforementioned system can replace a 4000 watts swamp cooler works for 6 hours a day.

Numerical and analytical studies are carried out to investigate natural convection in an inclined porous cavity filled with a volumetric heat source. Heat fluxes are imposed on the sidewalls to ensure a cooling process. The Darcy model is taken into account in the mathematical formulation of the problem. The density variation is modeled by Boussinesq approximation as the temperature values are limited. Numerical solutions are obtained for a wide range of governing parameters such as aspect ratio A, Rayleigh number R, inclination angle ϕ, and the dimensionless heat flux at the left active wall q L. The analytical solution is based on the parallel flow approximation and valid for A ≫ 1. The results elucidate an asymptotic tendency of the rate heat transfer with Rayleigh number. The normalized Nusselt number Nu L reach the maximum when ϕ = 80 deg and q L = 0.75. A good agreement between the analytical model and the numerical simulations is obtained in the case of a tall cavity.

- by Ana Maria Gruia
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- Iconography, Early Modern Era, Decorative Arts, Medieval Art

erschienen auf den Seiten: 259-275

- by Fabrice Amougou
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- Solar thermal, Heating and cooling systems

Health monitoring of infrastructure is very
important in the transportation and infrastructure industries.
Many nondestructive testing (NDT) techniques have been applied
for structural health monitoring including microwave NDT,
ultrasound, thermography, etc. Due to the complex materials
(composites, concrete, etc.) commonly used, it may be difficult to
thoroughly inspect a structure using one method alone. Thus,
hybrid NDT methods have also been developed. Recently, the
integration of microwave NDT and thermography, herein
referred to as Active Microwave Thermography (AMT), has also
been considered as a potential structural health monitoring tool.
This hybrid method uses microwave energy to heat a structure of
interest, and then the thermal surface profile is measured using a
thermal camera. This paper investigates the potential of AMT to
inspect rehabilitated cement-based structures. Preliminary
simulations and measurements provided herein indicate that
AMT has the potential to detect delaminations under carbon
fiber patches bonded to concrete.

- by Ali Foudazi and +1
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- Civil Engineering, Aerospace Engineering, Antennas & Radio Wave Propagation, Composite Materials and Structures
- by Henk Schellen
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- Archaeology, Physics, Cultural Heritage, Air pollution

Heating and cooling load calculations are critical to size Heating, Ventilating and Air conditioning (HVAC) systems and determine energy use of their operations. The ASHRAE recommended heating load calculation model is most commonly used for heating load calculations. It adopts a simplified approach by considering only steady-state conductive heat transfer. However, due to thermal storage effect, heat generated in daytime may still be stored in buildings and released at a later time. Such assumption leads to significantly over-sized heating systems which are usually accompanied by high initial cost and higher cost of energy use. This study therefore examines the thermal response and passive storage characteristic of heavy construction for typical office building in continental US states. By allowing space air to drift to reasonably lower values, buildings need to be warmed up before being occupied in the morning. The worst case conditions might happen during warm-up or beginning of occupied hours. This paper evaluates the optimal size of heating system which satisfies thermal comfort while taking advantage of passive thermal storage. Results show varying downsizing opportunities ranging from 14% to 54% across the US. These results have the potential of establishing new heating device design standards for certain climate classifications

- by Oluwaseyi Ogunsola and +1
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- Energy, Heat Transfer, Optimization techniques, Heating and cooling systems

The measurement of indoor climate in heritage buildings can provide valuable sources of data needed for an optimal use and management of the works of art exhibited inside. It is a fundamental technique to evaluate environmental damage and degradation processes, to support the protection, conservation and preservation of works of art, improving the quality of museum environments. This is particularly important when the old buildings have special architectural and historical value. In most cases, the buildings themselves are works of art and at the same time preserve various precious objects. The stability requirements of microclimatic conditions play a key role in the deterioration processes of the various materials of building and works of art. It is necessary to reduce variations in thermo-physical parameters because they are as damaging as their absolute values, ensuring a sufficient comfort level for users. In the present paper results from experimental measurements performed inside a historical building used as a museum, located in Fucecchio (near Florence, Italy), are discussed. A method based on the implementation of the current standard UNI EN ISO 13786, was used to study the heat transfer to and from a single thermal zone (one of the exhibition rooms) of the museum. Making some basic assumptions, the time-varying thermodynamic measures could be decomposed, by means of the Discrete Fourier Transform (DFT), into a sinusoidal frequency component. These components could be independently analysed by means of the norm above and the results combined to estimate the total heat transfer wave through the room envelope. These results can provide a useful support in decision making about the choice of the most suitable environmental control strategies such as passive control, controlled ventilation, shading and added insulation of building, modular and movable heating plant systems (e.g. radiant platform) and, if possible, Heating Ventilation Air Conditioning (HVAC) system. In addition, this method allowed an estimate of the time-course of the temperature on the internal surface of the walls, which is an important factor for optimally arranging the paintings inside the exposition rooms.

- by Roberto Boddi and +1
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- Cultural Heritage, Cultural Heritage Conservation, Heritage Conservation, Energy Efficiency Buildings

In this study, the results of the performance analysis of a WLHP system applied to a large mall building located close to Naples (South Italy) is presented. The investigation was carried out through a purposely developed dynamic simulation model conceived for building-WLHP systems analyses. Through such computer tool, hourly, daily and seasonal system energy, economic and environmental assessments can obtained. For the developed case study the results of the WLHP system optimization procedure are also reported. A comparison of the modeled WLHP system Vs. traditional HVAC ones is also performed. Encouraging energy, economic and environmental results are achieved.

- by Adolfo Palombo and +1
- •
- Sustainable Building Design, Energy Efficiency Buildings, Building Energy Simulation, Sustainable Energy
- by s s
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- Business, Hospitals, Heating and cooling systems, Domestic

We’re all familiar with the image of a soda can in the commercial. As the ice cold can beads up with moisture you are left longing for a refreshing cold drink. However it is less refreshing to be reminded that cold surfaces in our homes can bead up with condensation just like the soda can in the commercial. The cold surfaces in our home are prone to condensation too. Fine in the commercial, but unfortunately not so good in your home. In some climates mold can be hard to prevent. We explore ways you can avoid conditions that promote mold growth.

Remote inspection of underground heat supplying systems on the basis of aerial infrared thermography (AIT) is able to find latent leaks of hot water and other imperfections (malfunctions). Moreover, AIT data allow forecasting the places of future leaks and efficiently choosing the zones of heating lines for high-prior reconstruction, according to their actual technical condition, rather than their age.

It is true :) This study presents the annual operation profile of an average global container feet. The profile is used for cycle simulations and calculation of the energy consumption and the total equivalent warming impact (TEWI) in order to compare different refrigerant options (CO2;R32;R134a;R290;R1270).
The results show a promising potential for flammable refrigerants in terms of annual energy consumption savings, as well as reduction of TEWI and costs. On the other hand, the use of flammable refrigerants requires a detailed risk assessment to understand the different safety concerns for operation. The results of an operational mode risk assessment and a safety concept using flammable refrigerants are presented in the second part of this work.LoL(!).
Keywords: flammable refrigerants, Propane, risk assessment, reefer
refrigeration, inter-modal container
2014 MSC: 00-01, 99-00

Thermally-induced deformations of steering mirrors reflecting 100 J/10 Hz laser pulses in vacuum have been analyzed. This deformation is caused by the thermal stress arisen due to parasitic absorption of 1 kW square-shaped flat-top laser beam in the dielectric multi-layer structure. Deformation depends on amount of absorbed power and geometry of the mirror as well as on the heat removal scheme. In our calculations, the following percentages of absorption of the incident power have been used: 1%, 0.5% and 0.1%. The absorbed power has been considered to be much higher than that expected in reality to assess the worst case scenario. Rectangular and circular mirrors made of zerodur (low thermal expansion glass) were considered for these simulations. The effect of coating layers on induced deformations has been neglected. Induced deformation of the mirror surface can significantly degrade the quality of the laser beam in the beam delivery system. Therefore, the proper design of the cooling scheme for the mirror in order to minimize the deformations is needed. Three possible cooling schemes of the mirror have been investigated. The first one takes advantage of a radiation cooling of the mirror and a copper heatsink fixed to the rear face of the mirror, the second scheme is based on additional heat conduction provided by flexible copper wires connected to the mirror holder, and the last scheme combines two above mentioned methods.

- by David Vojna
- •
- Numerical Simulation, Heating and cooling systems, Thermal Stress, Optics and lasers

Fast and controllable surface acoustic wave (SAW) driven digital microfluidic temperature changes are demonstrated. Within typical operating conditions, the direct acoustic heating effect is shown to lead to a maximum temperature increase of about 10 °C in microliter water droplets. The importance of decou- pling droplets from other on-chip heating sources is demonstrated. Acoustic- heating-driven temperature changes reach a highly stable steady-state value in ≈3 s, which is an order of magnitude faster than previously published. This rise time can even be reduced to ≈150 ms by suitably tailoring the applied SAW-power excitation profile. Moreover, this fast heating mechanism can lead to significantly higher temperature changes (over 40 °C) with higher viscosity fluids and can be of much interest for on-chip control of biological and/or chemical reactions.

For promoting the diffusion of GSHP (Ground Source Heat Pumps) a tool for sizing these systems will be carried out in the H2020 research project named " Cheap GSHPs ". The paper presents the set up of a database with energy profile of a certain amount of buildings representative of the typology (single family houses, block of flats, office buildings) with different insulation levels and in different climatic conditions. Based on the weather analysis among European climatic files, twenty locations have been considered. For each location the overall energy and the mean hourly monthly energy profiles for heating and cooling (sensible and latent) have been calculated. Based on the results, the correlations with Degree Days (DD) for heating

- by Adriana Bernardi and +2
- •
- Heating and cooling systems, Energy profiles, Energy Profiles for Heating and Cooling of Buildings
- by VINCENZO BIANCO
- •
- Engineering, Economics, Sustainable Building Design, Built Environment

This paper deals with newly developed sliding mode controller
for heating-cooling processes. Basic principles of the algorithm are explained. The proposed strategy is applied to control of a laboratory heating-cooling model. Several experiments examining closed loop properties are performed. The obtained results are compared with
traditional PID control.

- by R. Škarda and +1
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- PID controller design, Heating and cooling systems, Sliding mode control
- by Kapil Choudhary and +1
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- Renewable Energy, Combustion, Performance, Heating and cooling systems

Removing the heat under the solar cells is important to reduce the thermal noise introduced by the solar. Today, there are many cooler designs. Each design has its own advantages and disadvantages in term of removing the heat under the solar cells. There are several methods currently available to reduce the heat, such as by using heat sink, a tunnel to direct the heat flows, a fan to blow the heat out and so on. As the heat is removed under the solar cells, the temperature of the solar cells drops accordingly. Hence, this cause the solar cells operate in stable mode and less noise is introduced in the DC output. In this research, a new approach to study the heat removal is proposed. The proposed idea is using fins with copper pipes run across the fins. This copper pipe carries water in and out to absorb the heat from the fins. The fins are used to conduct the heat and direct the heat to the copper pipe. It is believed that this method can reduce 85% of heat under the solar cells and it has a great advantage of not introducing the noisy sound when operate in a long time. In order to understand this design and operation, a simulation is carried out using SolidWork to show the thermal flows and how much the temperature can be reduced. SolidWork is chosen because this software has a thermal analysis. SolidWork allows the designer design a 3D object and run the simulation to study the effects. At the end of the research, a temperature reduction with and without using this proposed method will be shown and discussed. The difficulties of the design and detail of the heat flows under this propose method will be discussed and illustrated using appropriate mathematical tools.

- by Muhannad Al-Waily
- •
- Renewable Energy, Photovoltaic Cells, Heating and cooling systems, Obstacles

Chassein, Edith; Hummel, Marcus; Kranzl, Lukas; Maurer, Christiane, Cappelletti, Floriane; Münster, Marie; Ben Amer-Allam, Sara et al. (2017): Boosting renewable energy in heating and cooling. Fact sheet for six case studies. progRESsHEAT... more

- by Adriana Bernardi and +2
- •
- Geothermal Energy, Heating and cooling systems, Ground source heat pumps, Geothermal Exploration

Heat transfer inside wall-joint-fins systems is analyzed. The coupled two-dimensional energy equations of the wall and the joint-fin are
solved numerically using an iterative high order scheme finite volume method. Advanced fine analytical solution is proposed and various
closed form equations for different heat transfer augmentation indicators are obtained. Excellent agreement is noticed between the numerical
and the analytical results. Wall-joint-fins systems are more effective in transferring thermal energy when the joint-fin is made of
a highly conductive material. Moreover, varying the joint-fin lengths ratio may increase the system effectiveness by a factor of 1.2. In
addition, the maximum reported system effectiveness is 925% above that when both wall and joint-fin have same thermal conductivity.
The maximum system effectiveness which occurs at specific geometrical aspect factors increases as convective heat transfer coefficients
increase. Furthermore, the effectiveness and efficiency of the wall-joint-fins system increase as the relative joint-fins to wall volume ratio
increases. The wall-joint-fins efficiency is least affected by the joint-fin lengths ratio. Eventually, the heat transfer coefficient between the
joint-fin and the wall is identified. Finally, wall-joint-fin systems are recommended as heat transfer enhancing elements.

The combination of its sorption capacity, reaction enthalpy, melting temperatures around available industrial waste heat and solar source and high thermal efficiency (compared to others salt hydrates) makes strontium bromide and its two respective hydrates a potential material for low temperature energy storage and building applications. It is considered among suitable materials for low thermochemical and sorption energy storage application (N’Tsoukpoe et al. [7]) due to its high-energy storage density and end-user temperature. Strontium bromide is simultaneously considered as a phase change and a thermochemical material. A short analysis of the general physical and chemical properties such as thermodynamics, melting temperature, density, sorption kinetics, exergy, thermal conductivity, specific heat capacity and permeability highlights the advantageous properties. The review on the use of strontium bromide in pure or modified form is further extended to applications such as building structure, composite design for thermal storage, and heating and cooling. The usefulness and disadvantages of its use in closed/open processes are discussed. Possible solutions to issues are further presented or proposed. Downloaded copy here: https://authors.elsevier.com/a/1UcDV3In-8xkJV, until April 14, 2017.

- by Prof. Armand Fopah Lele
- •
- Design, Renewable Energy, Building, Heating and cooling systems

A novel polygeneration system is presented. System includes CPVT collectors, PEM fuel cell, absorption chiller and electrolyzer. The system provides heating/cooling, domestic hot water, electricity, hydrogen and oxygen. The system simple payback period is 12.5 years, 5.8 years in case of incentive. The optimal fuel cell nominal power results 100 kW. a b s t r a c t This paper presents a dynamic simulation model and an energetic and economic analysis of novel poly-generation system. The system integrates: cogenerative Proton Exchange Membrane Fuel Cell (PEMFC), Concentrated PhotoVoltaic-Thermal (CPVT) collectors, alkaline electrolyzer and single-stage LiBr/H 2 O absorption chiller. The plant is designed to supply electrical energy, space heating or cooling and domestic hot water for a small university building. The system produces hydrogen and oxygen, the first one is stored and then it is supplied to the fuel cell, while the second one is sold. The electrolyzer system is powered only by the CPVT collectors, only a small amount of the solar electrical energy is available to the user. Such electric energy along with the one produced by the PEM fuel cell are used by the user and/or supplied to the grid. The system is designed and dynamically simulated using TRNSYS software package. This study is based on a model previously developed by the authors. In particular, the system was modified in order to implement the new components (CPVT, alkaline electrolyzer, hydrogen and oxygen system) in this work. Special attention is paid to the control strategy of the proposed system in order to achieve the optimal system configuration. Daily, weekly and yearly results carried out with the dynamic simulation are presented. Finally, a sensitivity analysis was performed in order to determine the system performance as a function of the main design parameters. The energetic and economic analysis shows that the system can ensure significant energy savings and it can be profitable in presence of a capital investment incentive. The total energy efficiency of the CPVT collectors, calculated with respect to the beam radiation , is above 80% and the fuel cell electrical and thermal efficiencies resulted 35.0% and 43.4%, respectively. The hydrogen production of the electrolyzer system covers 4.3% of the fuel cell hydrogen demand. The Simple Pay Back period, in case of incentive, results of about 5 years when the optimal FC nominal power of 100 kW is selected.

- by Alessandro Mauro and +2
- •
- Renewable Energy, Fuel Cells, Heating and cooling systems, Transient analysis

The main objective of this research work is to provide partial cooling to the Non-A/c railway's coaches, like sleeper and passenger coaches, for the short distant journey train through the air-duct made in the roof of the coaches. Partial cooling is the process of reducing the temperature of hot air coming to the coaches up to some extent using chemical solution based on simple heat transfer concept. As we know, there is no any cooling system for Non-A/c coaches in the railway, so it is great difficult to travel in these coaches in summer time. This paper describes a simple arrangement, which work on the simple heat transfer process, of a new component including a plastic container having the chemical solution and a hollow coiled pipe of Aluminium which passé through the solution. This arrangement doesn't have any electrical component and it can be fixed easily within air-ducts.

- by rathin dutta and +1
- •
- Heating and cooling systems, Railway Engineering, Ammonium Chloride
- by Matteo Agostini
- •
- Engineering, Materials Science, Microfluidics, Surface Acoustic Waves

In this study a solar driven absorption cooling system is offered for a hotel. Solar energy is only used in absorption chiller. The payback time of the offered system with different scenarios are investigated. Solar collectors and absorption chiller price are the main contributors to the total system price. The effects of the unit prices of the absorption chiller and solar collectors depend on the technology development. However, electricity prices increases day by day due to the increased fuel prices. Also, storage option is taken into account to increase the load factor of the offered system. The effect of the carbon prices are also investigated for the offered system for different ton prices of the carbon. The best and worst scenarios are given with respect to the variation of the prices and load factor. The results show that, the payback time changes 2.18 to 20.3 years. With 2010 prices with 10 $ per ton carbon credit the payback time is calculated 10.1 years. However, the cost ...

- by ehsan amirabedin
- •
- Engineering, Heating and cooling systems, Gazi University, Solar Cooling Systems

For promoting the diffusion of GSHP (Ground Source Heat Pumps) a tool for sizing these systems will be carried out in the H2020 research project named “Cheap GSHPs”. The paper presents the set up of a database with energy profile of a certain amount of buildings representative of the typology (single family houses, block of flats, office buildings) with different insulation levels and in different climatic conditions. Based on the weather analysis among European climatic files, twenty locations have been considered. For each location the overall energy and the mean hourly monthly energy profiles for heating and cooling (sensible and latent) have been calculated. Based on the results, the correlations with Degree Days (DD) for heating and cooling have been found in order to generalize the results to have pre-calculated profiles for sizing GSHP.

- by mark B Luther
- •
- Engineering, Renewable Energy, Energy Consumption, Instrumentation

In this study, in a water heating system, the initial temperature of the water in the tank is assumed to be 45 °, and a hot water is added to the tank at 120 ° to heat it to 100 °. This water enters the tank at 30 liters per minute and the tank contains 3000 liters of water. The mathematical solution and modeling of this temperature change in the tank from t = 0 to t = 40th minute by both analytical method and Euler method, which is a numerical method, was carried out and transferred to graphics in detail.

- by Faruk Tepe
- •
- Heating and cooling systems, Hot water system

PDF about Sydney Hot Water Systems.

- by Sydney Hot Water Systems
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- Heating and cooling systems, Solar Water Heater, Heating