Georgios A FloridesCyprus University of Technology · Department of Electrical Engineering, Computer Engineering and Informatics
Georgios A Florides
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120
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January 2008 - September 2016
Publications
Publications (120)
A large number of ground-source heat pump (GSHP) systems have been used in residential and commercial buildings throughout the world due to their attractive advantages of high energy and environmental performances. In particular, GSHPs constitute a proven renewable energy technology for space heating and cooling. This paper provides a detailed lite...
Geothermal energy, a type of renewable energy obtained from the Earth, can be used by Ground Source Heat Pumps (GSHPs) for space heating and cooling. GSHP systems extract/reject heat from/into the earth via a network of pipes or tubes known as Ground Heat Exchangers (GHEs),. GHEs can be horizontal or vertical and come in a variety of forms, includi...
Science studies natural phenomena or uses laws, theories, models and mechanisms to explain them, which are revised when new evidence emerges. However, Science cannot give answer to all questions that may arise. The benefits of science are well known and there is no reason to expand on them. It is of interest though to examine the structure and fact...
Ground Heat Exchangers (GHEs), buried in the ground either horizontally or vertically (in a borehole), are coupled with a heat pump to form a Ground Source Heat Pump (GSHP) system, which is a type of Renewable Energy System that exploits geothermal energy for space heating and cooling. GSHP systems are proposed as an alternative to conventional Air...
Abstract: This paper addresses the topic of site characterization for the design of Shallow Geothermal Energy (SGE) systems, namely of thermoactive geostructures, which are geotechnical structures, such as piles, retaining walls and tunnel linings, also used as heat exchangers as part of closed-loop SGE systems. Such solutions, being increasingly a...
The wide adoption of heat recovery technologies in industry is hampered by specific “barriers” related to both technical and non-technical issues. This paper attempts to determine these barriers and make recommendations on how to address them. First, a literature review of related material is presented. Among numerous barriers, the main ones identi...
Industrial processes are characterized by energy losses, such as heat streams rejected to the environment in the form of exhaust gases or effluents occurring at different temperature levels. Hence, waste heat recovery (WHR) has been a challenge for industries, as it can lead to energy savings, higher energy efficiency, and sustainability. As a cons...
The 2016 finds of Palpa, Ica, Peru, assumed to be archaeological in nature, recently received due attention by the scientific community. To help clarify the issue, the current study aims to scientifically examine, through CT-scan analysis, the skull of one of the small bodies, and compare it to the braincase of llamas and alpacas, which are common...
Ground Source Heat Pumps (GSHPs) are used for space heating and cooling, where the Ground Heat Exchangers (GHEs) are used to extract or reject heat from/to the ground. GHEs come in various configurations, vertical or horizontal. Compared to Air Source Heat Pumps (ASHPs), GSHPs, albeit having a higher installation cost, achieve a better coefficient...
Shallow Geothermal Energy Systems (SGESs) constitute Renewable Energy Systems (RES), which find application in the residential sector through the use of Ground Source Heat Pumps (GSHPs). GSHPs are associated with Ground Heat Exchangers (GHEs), whereby heat is gained/lost through a network of tubes into the ground. GSHPs have failed to flourish in t...
Thermal processes account for 70% of the EU industry final energy, with 30% thereof being wasted through losses. This fact has been a motivating factor toward applying various technologies and methods for waste heat recovery. Already such technologies exist and are applied in many industrial sectors, while some “new” technologies have also been tes...
Shallow geothermal energy systems (SGES) may take different forms and have recently taken considerable attention due to energy geo-structures (EGS) resulting from the integration of heat exchange elements in geotechnical structures. Still, there is a lack of systematic design guidelines of SGES. Hence, in order to contribute towards that direction,...
Underfloor heating systems provide comfort due to the natural heat flow distribution by a network of pipes, conventionally connected to a heat pump operating at low temperatures. To this extent, a renewable energy source could be an alternative solution. Acting as a case to investigate such systems, the Mediterranean island of Cyprus with a plethor...
This chapter examines solar space heating and cooling systems. Initially, the basic system configurations are presented which include active solar systems in which direct circulation systems, indirect water-heating systems, and air water-heating systems are presented; space heating and service hot water systems which include air and water systems,...
Ground heat exchangers in conjunction with shallow geothermal energy system applications have received significant attention in the case of renewable energy. Soil thermal properties such as thermal conductivity and specific or volumetric heat capacity are important aspects for the design of such systems, affecting the performance. They can be obtai...
Industrial processes are currently responsible for nearly 26% of European primary energy consumptions and are characterized by a multitude of energy losses. Among them, the ones that occur as heat streams rejected to the environment in the form of exhausts or effluents take place at different temperature levels. The reduction or recovery of such ty...
The recent evolution of the Ground Source Heat Pumps (GSHPs) has initiated the debate whether it is economically feasible to install a GSHP as an alternative to an Air Source Heat Pump (ASHP). A typical house heating/cooling load for moderate climates is presented and discussed for comparison purposes. For this purpose, the thermal response of the...
The paper focuses on the methodology for modeling the thermal response of vertical Ground Heat Exchangers (GHEs), when imposing underground water flow and a temperature gradient on the numerical model to represent the temperature of the depth profile. Four underground layers with different properties were studied, in order to identify their contrib...
In the European Union (EU), industrial sectors use 26% of the primary energy consumption and are characterized by large amounts of energy losses in the form of waste heat at different temperature levels. Their recovery is a challenge but also an opportunity for science and business. In this study, after a brief description of the conventional Waste...
Soil thermal characterization is an important aspect affecting the performance of Ground Heat Exchangers (GHE) in a Shallow Geothermal Energy (SGE) system application. Thermal conductivity and specific heat capacity are the sole requirements in designing such systems and can be obtained using empirical prediction models, laboratory tests and in sit...
Increasing use of the ground as a thermal reservoir is expected in the near future. Shallow geothermal energy (SGE) systems have proved to be sustainable alternative solutions for buildings and infrastructure conditioning in many areas across the globe in the past decades. Recently novel solutions, including energy geostructures, where SGE systems...
Increasing use of the ground as a thermal reservoir is expected in the near future. Shallow geothermal energy (SGE) systems have proved to be sustainable alternative solutions for buildings and infrastructure conditioning in many areas across the globe in the past decades. Recently novel solutions, including energy geostructures, where SGE systems...
Increasing use of the ground as a thermal reservoir is expected in the near future. Shallow geothermal energy (SGE) systems have proved to be sustainable alternative solutions for buildings and infrastructure conditioning in many areas across the globe in the past decades. Recently novel solutions, including energy geostructures, where SGE systems...
In Ground Source Heat Pump systems, the heat exchange rate is an important factor with regard to the initial cost of the system. When the Ground Heat Exchanger (GHE) is installed in a lithology with high thermal properties in the presence of groundwater, the heat exchange rates are larger than in the cases with poor thermal response of the ground a...
Industrial processes are currently responsible for almost 26% of European primary energy consumptions (275 Mtoe/yr). Furthermore, most of the energy sources that drive the industrial sector are fossil fuel based. Every industrial process is characterised by a multitude of waste heat streams at different temperature levels whose recovery would undou...
This chapter examines solar space heating and cooling systems. Initially, the basic system configurations are presented which include active solar systems in which direct circulation systems, indirect water-heating systems, and air water-heating systems are presented; space heating and service hot water systems which include air and water systems,...
Cyprus is currently the leading country in the world with respect to the application of solar water heaters for domestic applications, with more than 93 % of the houses equipped with such a system. The great majority of these solar water heaters are of the thermosiphonic type. Currently, the knowledge about the parameters affecting the ‘thermosipho...
The objective of this paper is to examine the factors affecting the sizing and positioning of Ground Heat Exchangers (GHEs) in Cyprus. This is achieved through the investigation of the influence of the temperature, thermal conductivity, specific heat and density of the ground as well as pipe diameter on the performance of GHEs using computer softwa...
The aim of this paper is to show a practical way of estimating the thermal ground properties, namely the ground thermal conductivity, and in particular the thermal diffusivity and the volumetric heat capacity in a reliable manner, for sizing Ground Heat Exchangers (GHEs). A well-known thermal model, proposed by Blackwell in 1954, is applied and is...
Previous studies in Cyprus classified the island in the category of low enthalpy with high potentials in the usage of geothermal energy for space air-conditioning. Due to the little existing information about the underground thermal properties, an extended geological sampling has been carried out on the island. Measurements of thermal properties ha...
Multiple layers of ground and the flow of groundwater in some layers have a significant effect on the cooling of vertical heat columns and heat exchangers. This paper investigates the important implication on the design of the Ground Heat Exchanger with regard to their heating effect. For this reason, a thermal model is constructed in COMSOL Multip...
The field of microfluidics utilizes micron-scale devices to control the flow of fluids. The principal application is the manipulation of very small volumes of fluids on the order of nanoliters to femtoliters that are typically seeded with nanoparticles. Hence the control and sorting of nanoparticles is a primary goal using this technology. There is...
In this paper a neural network is used for the generation of a contour map of the ground conductivity in Cyprus. Archived data of thermal conductivity of ground recorded at 41 boreholes are used for training a multiple hidden layer neural network with feedforward architecture. The correlation coefficient obtained between the predicted and training...
Using finite element analysis (FEA), a model has been constructed to predict the thermo-fluidic and optical properties of a microstructure optical fibre (MOF). The properties under study include external temperature, input water velocity and optical fibre geometry. Under laminar flow the steady-state temperature is dependent on the water channel ra...
Recent years have seen considerable advances in organic photovoltaics (OPVs), most notably a significant increase in their efficiency, from around 4 % to over 10 %. The stability of these devices, however, continues to remain an issue that needs to be resolved to enable their commercialization. This review discusses the main degradation processes o...
Photovoltaic (PV) materials are increasingly being incorporated into the construction of new buildings for generating electrical power and are used to replace conventional building materials in parts of the building envelope such as the roof, skylights, or facades. Also photovoltaic systems may be retro it - integrated into existing buildings. The...
Microfluidics are important micro-scale devices that can be used to manipulate very small volumes of fluids on the order of nano- to femto-liters. The control and sorting of nano-particles is a primary goal using this technology. There is particular interest in the use of microstructure optical fibers for the heat transfer of fluids, whereby the gu...
A finite element analysis (FEA) model has been constructed to predict the thermo-fluidic and optical properties of a microstructure optical fiber (MOF) accounting for changes in external temperature, input water velocity and optical fiber geometry. Modeling a water laminar flow within a water channel has shown that the steady-state temperature is d...
This paper discusses the effect of the greenhouse phenomenon and CO2 on global climate and suggests that numerical models that lack adequate knowledge of fundamental related factors cannot be used to extract 'sound" conclusions. A very basic demonstration of this is done through a simple comparison between estimates of the forecast for global tempe...
This paper describes the mathematical modeling of vertical and horizontal GHEs (ground heat exchangers) and compares their efficiency. The model used calculates the heat flow in the fluid, tubes, grout and ground. The vertical U-tube GHE is represented by two 100 m lines, embedded in four different types of ground with an additional bottom base. Th...
Heat pumps (HP) attain higher efficiencies and save energy when they are coupled to ground heat exchangers (GHEs). For this reason we compare, by modeling, the efficiency of the vertical and horizontal GHEs which are two basic types. The modeling of the vertical heat exchanger is represented by two tube lines of 100 m in length, embedded in four di...
The efficiency of ground-source heat pumps depends on the correct sizing of the associated ground heat exchangers (GHEs). Multiple ground layers with regard to GHE and the presence of more than one loops in each borehole (multiple U-tubes) are sparsely raised in the literature. Therefore the accurate prediction of the performance of the GHE under t...
A Project funded by the Research Promotion Foundation of Cyprus was undertaken by the Cyprus University of Technology and other collaborators, to investigate and determine the geothermal parameters of the ground in Cyprus since such information is currently unavailable. The purpose of this paper is to report on the ground temperatures collected by...
This chapter examines solar space heating and cooling systems. Initially, the basic system configurations are presented which include active solar systems in which direct circulation systems, indirect water-heating systems, and air water-heating systems are presented; space heating and service hot water systems which include air and water systems,...
In this paper a neural network is used for the generation of geothermal maps (contours) of temperature at three depths (20, 50 and 100 m) in Cyprus. Archived data of temperature recorded at 41 boreholes is used for training a suitable artificial neural network. The complete data was randomly divided into a training and validation dataset. The neura...
Earth heat exchangers are essential parts of the ground-source heat pumps and the accurate prediction of their performance is of fundamental importance. This paper presents the development and validation of a numerical model for the simulation of energy flows and temperature changes in and around a borehole heat exchanger when a fluid circulates th...
Microfluidics are important micro-scale devices that can be used to manipulate very small volumes of fluids on the order
of nano- to femto-litres. The control and sorting of nano-particles is a primary goal using this technology. There is
particular interest in the use of microstructure optical fibres for the transfer of fluids, whereby the guide...
Energy consumption for most sectors in Cyprus is not well monitored and therefore their impact on greenhouse gases emissions has never been estimated. Thus, the aim of this study was to estimate the energy consumption in livestock breeding activities in Cyprus, and estimate the respective emissions of greenhouse gases. The energy consumption consid...
The ground can be used as an energy source, an energy sink, or for energy storage and for this reason ground characteristics should be available. Therefore the purpose of this paper is to present the recorded ground temperatures at eight representative sites of Cyprus, in relation to depth, time of year, geology and altitude and discuss the efficie...
The knowledge of the thermal behaviour of the ground and the factors affecting it are important for many construction projects and for using the ground as heat storage or a heat exchange media. Not enough information exists regarding the thermal behaviour of the ground in Cyprus and this is one of the main interests of this study. The ground temper...
In isolated energy systems with no indigenous sources of energy such as the one of the Republic of Cyprus, the renewable energy option is the only alternative to achieve energy independence. Though, the relative technological maturity of renewable energy sources and their satisfactory efficiencies, their implementation has not reached the expected...
The significance of the residential building sector in terms of energy consumption is well acknowledged. In this view the knowledge of the way the residential building stock of Cyprus behaves in terms of energy consumption is quite valuable since it will assist policy makers to formulate targeted measures aiming the improvement of energy efficiency...