Floor Temperature Research Articles

Development of a new method to estimate thermal performance of multilayer radiant floor

.For a pipe-embedded concrete radiant floor, its thermal performance is essential to maintain the desired cooling/heating capacity and indoor thermal comfort. A good temperature distribution of the floor surface is very important in order to prevent occupant discomfort and avoid possible condensation in the case of floor cooling. In this study, a heat transfer model of a three-layer floor was developed by coupling 2-D and 1-D heat transfer problems. The analytical solution was developed and validated. The results of the calculations are in a good agreement with the experiments. The absolute error between the calculated and the measured floor surface temperatures was within 0.4℃. The maximum relative error was within 2.2%. The proposed method can be utilized to calculate the thermal performance of a floor, either a one-layer floor, a two-layer floor or a three-layer floor. The thermal resistance of the floor with different structures can be calculated and used to estimate thermal performance of the floor. For the typical radiant floor, the range of thermal resistance is approximately 0.15-0.45 m2K/W with a pipe spacing from 0.1 to 0.5 m. With the overall floor temperature obtained, it is possible to identify the percentage of the floor area with a temperature higher than the limit and to estimate the overall and local occupant comfort. Based on the thermal resistance of the floor, an ε-NTU method will be developed in the future study for design of a radiant floor.

Anionic Copolymerization of Styrene Sulfide with Elemental Sulfur (S8).

The superior ability of thiiranes (episulfides) to undergo ring-opening polymerization (ROP) in the presence of anionic initiators allows the preparation of chemically stable polysulfide homopolymers. Incorporation of elemental sulfur (S8) by copolymerization below the floor temperature of S8 permits the placement of a large quantity of sulfur atoms in the polysulfide mainchain. The utility of styrene sulfide (2-phenylthiirane; StS) for copolymerization with elemental sulfur is reported here. A few polysulfides differing depending on the initial ratio of S8 to StS and copolymerization time were synthesized. Various spectroscopic methods (1H NMR, 13C NMR, Raman spectroscopy and FTIR spectroscopy) were applied to characterize the chemical structure of the copolymers. Additionally, the phase structure and thermal stability of the synthesized polysulfides were investigated using DSC and TGA, respectively. The successful anionic copolymerization of styrene sulfide and elemental sulfur has been demonstrated.

Effect of installation height of indoor unit on field heating performance of room air conditioner

The room air conditioner (RAC) is considered the most suitable space heating method for residential buildings without domestic heating in the mild climate zone. The heating performance of RACs has been well researched in laboratories. However, the field performance of RACs is far from the laboratory experimental results owing to their installation and maintenance procedures. This study investigates the impact of the indoor unit installation height of RACs on their field performance during heating. By adjusting the height of the indoor unit, the energy performance and thermal sensation indexes are verified. An experiment is carried out to test the thermal comfort and energy performance simultaneously, which comparatively reflects the difference between different installation heights. The indoor air temperature and related parameters, predicted mean vote, vertical temperature difference, floor temperature, draft, and asymmetric thermal radiation are used to evaluate the indoor comfort. The heat capacity and coefficient of performance are used to assess the energy performance. Experimental results show that the installation height of the indoor unit affects the energy performance significantly. Generally, the heat capacity and coefficient of performance for lower installation heights are higher than those for higher installation heights. Furthermore, lower the installation position, the easier it is to create a comfortable indoor environment.

The effect of the building blind area heat insulation on heat losses through the floor on the ground

The relevance of the problem under studying is the appearance of non-traditional heating insulation structures of the floor on the ground, that can not be subject to calculations of heat losses using the existing methods. The purpose of this article is to find out the average characteristic heat transfer resistances in the design zones adopted in the Russian Federation for thermal protection of the floor on the ground by heat insulating the blind area of the building. Factors essential for possible elimination of condensation on the junction of the floor and the exterior walls were evaluated, as well as the possible maintenance of the floor temperature at the border of the serviced area not below specified values. The method of investigation is the annual calculation of unsteady thermal regime of flooring with the soil massive by finite difference method according to the implicit scheme. As the results we can state a significant impact of the type of soil on the heat loss through the ground floor, an insignificant impact of the width and thickness of the insulated building blind area. The most critical for the possibility of using the blind area heat insulation is the practical inability to provide acceptable temperatures of the floor at the wall-to-floor junction and on the border of the serviced zone. The main conclusion is that the heat insulation of the building blind reaches its goals at the room temperature of 10 °C. But it needs additional small heat insulation of the floor on the ground itself at a room temperature of 20°C and 30°C.

Hydrothermal areas, microbial mats and sea grass in Paleochori Bay, Milos, Greece

ABSTRACT The study presents a 1:3300 scale map, encompassing an area of 1.05 km2, depicting the first detailed map of the shallow-water water hydrothermal system in Paleochori Bay, Milos, Greece. The seafloor was mapped using orthophotos acquired by a drone survey and processed using ArcGIS. The map shows the distribution of white microbial mats, former microbial mats, sea grass and ‘normal’ sand down to a depth of 15 m. Generation of a comprehensive map with native shapefiles and layer files, where any GPS coordinate in Paleochori Bay can be obtained, allows to target specific locations for data collection, rather than resorting to vague site descriptions, as has been the practice in the past. Sea floor temperature measurements carried out by Scuba divers in conjunction with GPS coordinates were mapped and interpolated to evaluate the temperature distribution in Paleochori Bay, which in turn supports the overall understanding of the hydrothermal system.

Artificial hollows provide an effective short-term solution to the loss of natural nesting hollows for Carnaby's Cockatoo Calyptorhynchus latirostris

The ecology of one breeding population of Carnaby's Cockatoo Calyptorhynchus latirostris has been studied at Coomallo Creek, Western Australia, since 1969. A wildfire destroyed breeding habitat in part of the study area and adjoining areas in late December 2009. An increase in the number of breeding attempts the following year suggested that hollows were probably limiting. From 2011, the number of hollows available to the cockatoos was increased by repairing derelict natural hollows and providing artificial hollows. By 2017, cockatoos had access to 87 natural and 68 artificial hollows the approximate dimensions of natural hollows. Artificial hollows were readily accepted, however there were significant differences in the probability of hollows being used due to location and land use type. Despite floor temperatures of black and white artificial hollows being warmer than those of natural hollows, there were no significant differences in the probability of hollow use, the probability of breeding failures, and nestling condition in either white or black artificial hollows or natural hollows. The number of breeding attempts rose from 52 in 2011 to 127 in 2016 indicating that management intervention was effective. Between 2011 and 2018, artificial hollows provided 45% of available hollows and 54% of breeding attempts were made in them. By 2018, the number of breeding attempts in the area was 112% higher than in 2011. Artificial hollows provide an excellent short-term solution to the continuing loss of natural hollows. However, without extensive re-establishment of breeding and foraging habitat, the future for Carnaby's Cockatoo is uncertain.

Environment in stone chamber of an unexcavated tumulus and preservation of buried relics: Part 1. Environmental monitoring for simulated tumulus

Japan has many unexcavated tumuli, most of which were buried along with artifacts of precious cultural heritage. For such a tumulus, it is essential to understand how changes in its exterior environment affect its interior environment, and how those interior changes affect the deterioration of the relics buried in the stone chamber. In this study, an underground space was constructed in the forest of the Katsura Campus of Kyoto University to simulate the environment of an unexcavated tumulus, and long-term monitoring was implemented in the simulated stone chamber, including the temperature, humidity, water potential, wetness, and oxygen and carbon dioxide concentrations, along with metal corrosion tests. This article is focused on environmental monitoring, and the results demonstrate that the simulated tumulus has the general characteristics of the hygrothermal environments of an unexcavated tumulus that has small temperature fluctuation and near-saturation humidity. The ceiling of the simulated chamber condensed significantly from October to April, which is related to the variations of the ceiling and floor temperatures. Also, the wetness of the walls in the simulated chamber was affected by rainfall. The oxygen concentration in the simulated stone chamber varied in the range of 13%–19% in 2015, and the variation of carbon dioxide concentration in the simulated stone chamber was contrary to the oxygen concentration and varied in the range of 3%–9% in 2016. The oxygen concentration in the stone chamber was similar to that in the surrounding soil that decreased at times of rainfall, contrary to the fluctuations in the soil water content.

Thermal Comfort Analysis of Combined Radiation-Convection Floor Heating System

In this paper, a novel combined radiation-convection floor heating system is shown. This study uses practice-based learning and investigated the thermal performance of a combined radiation-convection floor heating system with a water heat pump system by evaluating the thermal environment and energy consumption in an experimental test. A new method that analyzed the thermal performance of four different controls was developed and applied. The results of the surface temperature distributions demonstrated that Mode 1, which uses only convection, had the lowest floor temperature and was thus considered inappropriate for occupants who sleep on the floor. By contrast, Modes 2, 3, and 4 showed high floor surface temperatures as hot water was supplied to the radiant heating panel. The predicted mean vote (PMV) results suggest that radiant floor heating is not appropriate for intermittent heating. In other words, occupants of single residences who return home at night will experience a long period of discomfort if they heat their room using floor heating. In this case, Mode 1, which is convection heating, and Modes 3 and 4, which represent mixed modes provide a more comfortable environment. The difference between this experimental study and previous research is that four different control modes for a combined radiation-convection system were evaluated based on the same location of the equipment in a laboratory. Furthermore, we studied the long-term real-scale thermal performance using panel and energy consumption.

Microstructural and mechanical assessment of the causes of failure of floors made of polyurethane-cement composites

The article presents the results of microstructural and mechanical testing of a floor made of polyurethane-cement composite significantly damaged after short-term use. The floor is located in a large-scale production and warehouse building. There was a lot of damage, including local abrasions, roughness, burns, and burning of the floor, which all threaten the safety of its use. Based on the carried out tests, errors in the execution of the tested floor were excluded and it was shown that the technology of its execution was correct. It was demonstrated, on the basis of research, that the reason that led to the damage was the improper use of the floor. This improper use consisted of allowing forklift drive wheels to spin pallets in order to deliver them with goods when adding or picking pallets to or from the pallet stack. The consequence of spinning was the rapid local increase in floor temperature, which caused a thermal shock to which the floor was not resistant.

Characteristics of zooplankton community in North Yellow Sea unveiled an indicator species for the Yellow Sea Warm Current in winter: Euchaeta plana

Zooplankton distributions are largely influenced by both biotic and abiotic factors in the surrounding environment. Some zooplankton species can be used as bio-indicators for particular currents and water masses to help discover the dynamics of water current in the ocean. In this study, we investigated the distribution of zooplankton in North Yellow Sea (NYS) during winter when the Yellow Sea Warm Current (YSWC) influenced that area. Zooplankton communities in the NYS were dominated by temperate and warm-temperate species, such as Calanus sinicus, Paracalanus parvus, Acartia bifilosa, and Sagitta crassa. Two warm-water species, Eucheata plana and Sagitta enflata were also present. Cluster analysis grouped NYS zooplankton into three communities, the Shandong Coastal Community (SCC) in the Shandong neritic area, the Yellow Sea Central Community (YSCC) in the central waters of the NYS, and the Liaoning Coastal Community (LCC) in the Liaoning neritic area. Abundances varied significantly among these communities, with an average of 102.2 ind./m3 in SCC, 179.8 ind./m3 in YSCC, and 1 244.2 ind./m3 in LCC. Depth and the bottom (3 m from the sea floor) temperature were likely the primary abiotic factors influencing zooplankton distributions. The appearance of E. plana, an indicator species for the YSWC path, indicated a significant northwestward trend for the YSWC in 2007.

Liquid cooling system for a high power light emitting diode of an automotive headlamp and its effect on light intensity

The automotive lighting industry is adopting compact cooling systems for high power light emitting diodes (HPLED) to overcome the heating issues in headlamps. Today, nano-particle based fluids are becoming popular as coolants as it is more effective than conventional coolant like water. The present work uses nano-fluid which is prepared using 100 percent ethylene glycol with 35 nm spherical shaped alumina nanoparticle with 1 percent volume concentration for HPLED cooling system. Using a custom made copper tube heat exchanger, experiments were conducted to study the performance of the cooling system using nano coolant and double distilled pure water as second coolant and results were compared. A popular Indian SUV headlamp that uses a halogen bulb was chosen for the study as it has space to accommodate the cooling system. Experiments were conducted by operating the HPLED at its maximum power and by varying the coolant flow rate. The performance of headlamp is studied by means of the light intensity measured at 49 test points on the floor surface and temperature measured at various points like LED junction and heat exchanger input and output. The junction temperature influences the light intensity of the LED. Lesser the junction temperature more will be the light intensity. It was found from the results that the junction temperature reduced by 26 percent with the help of the nano-fluid based cooling system. It is also found that the light intensity improved by 30 percent when the nano coolant was circulated at 0.3 m/s.

EARLY STAGES OF NEEDLE LITTER DECOMPOSITION IN A COWBERRY PINE STAND IN THE MIDDLE TAIGA OF KARELIA

Plant litter decomposes via several stages, the most intensive one being the early stage, when it is mostly readily extractable compounds that are released, contributing to annual nutrient cycling. The aim of this study was to find patterns in the rate of initial decomposition of needle litter depending on the ambient hydrothermal conditions in a cowberry pine stand both in general and in different ground vegetation microgroups. The measured parameters were air temperature and relative humidity, temperature of the forest floor and underlying soil horizons, amount and pH of precipitation and percolating water. The effect of mean monthly values of these parameters on the rate of needle litter decomposition in specific months during the first growing season was estimated both for the entire stand and under different ground vegetation microgroups. Studies have shown that the rate of needle decay is influenced the most significantly by hydrothermal parameters associated with forest floor temperature and moisture. The effect of the communitymicrogroup structure becomes visible only late in the growing season in the lichen-dominated ground vegetation microgroup, probably owing to the seasonal excess of moisture in its forest floor. Differences in needle decomposition rates between ground vegetation microgroups vanish during the winter season under the effect of abiotic factors. The degree of needle fall decay in the cowberry pine stand in the middle taiga subzone was 31.36 ± 3.32 % after the first growing season (110 days), and 42.16 ± 0.02 % over most of the annual cycle (335 days).

Thermal investigation on the attics of buginese traditional houses in South Sulawesi

This study aims to investigate the thermal conditions of the attic of traditional Buginese houses in the climate of South Sulawesi. The analysis is carried out based on data surveyed from eight houses. The recorded data includes both attic internal weather data and the measured environmental weather starting at 08.00 to 16.00 Central Indonesia Time (CIT). Measurement results showed high temperature in the attics, ranging from 30.7 °C in the morning to 51.1 °C in the middle of the day. Relative humidity minimum of 17.3% at midday and the highest is 67.1% in the morning. The roofs temperature can reach 67.7 °C before midday. The temperature on the attic floor between 24.9 °C in the morning to 43.0 °C in the middle of the day. The difference in the surface temperature of the attic floor guesses to be an average of 1 °C higher than the ceiling surface. Environmental weather factors have the most dominant influence on attic thermal performance.

Study on heating capacity and heat loss of capillary radiant floor heating systems

Radiant floor heating systems with the distinct advantages of low-temperature water supply, energy saving, uniform room temperature and well thermal comfort, are widely used in residential and office buildings in China. And those radiant floors embedded with capillary pipes have been increasing in popularity because of better thermal performance. In this paper, a new simplified calculation for heating capacity, heat loss and surface temperature of radiant heating floor with high-performance insulation layer was provided and validated by measured as well as numerical simulated data. By the simplified calculation method, the influence of each layer material on the heat transfer of capillary radiant heating floor have been analyzed and results show that, (1) the heating capacity will decreased with the increasement of pipe spacing and the descending slop is decided by the ratio of pipe spacing to the equivalent distance from pipes to the room environment; (2) thermal resistance of pipes could be ignored when it is twice more than that of filling material, or it will have negative influence on heating capacity with the increase of pipe spacing.

Thermal comfort in Supermarket's refrigerated areas: An integrated survey in central Italy

Thermal comfort conditions in supermarkets have been barely investigated in the past and only few meaningful studies have been carried out involving customers and staff. In this paper, the results of an integrated investigation on thermal conditions of customers and staff in refrigerated areas of four supermarkets in Central Italy are presented and discussed. Microclimatic surveys demonstrated that thermal comfort conditions for staff were generally consistent with ISO 7730 requirements. To the contrary, considering worn clothes, the thermal sensation predicted for customers was generally turned towards the cold both in autumn and summer with PMV values often below −2.The analysis of the local microclimatic parameters revealed low floor temperatures and a meaningful cold air stratification characterized by air temperature vertical differences measured between head and ankles up to 8–9 °C in case of open cabinets. In summer, due to the lower air temperature values (compared to the outdoor) combined with the usual low thermal insulation of clothes, the thermal environment is cold and the IREQ model revealed dangerous conditions for customers in three of the investigated areas with DLE (Duration Limit of Exposure) of about 40 min. In autumn, DLEs largely exceeded 1 h. Results of the subjective investigation carried out in two sales points for 35 customers were consistent with the objective survey and revealed higher percentages of dissatisfied in case of women. Finally, local discomfort due to cold feet effect seemed to be more consistent for women due to the low clothing distribution in lower parts of the body.

A comparison of the thermal comfort performances of a radiation floor cooling system when combined with a range of ventilation systems

This study conducted a series of computational fluid dynamics simulations to evaluate the thermal comfort performance of a radiant floor cooling system when combined with different ventilation systems, including mixed ventilation (MV), stratum ventilation (SV), displacement ventilation (DV) and ductless personalized ventilation (DPV). A window temperature of 32°C and three different floor temperatures including 20, 22 and 24°C were set in summer. We used the vertical air temperature differences (VATD) at ankle and head level, the percentage of dissatisfied, the draught rate at the ankle level and the equivalent temperature as our main evaluation indices. Our results show that the VATD in DV system can reach up to about 5°C, compared with about 2°C in MV and SV systems. For the DPV system, there is only a marginal drop in the VATD. For the DV and DPV cases, with a rate of air changes per hour (ACH) of 2.4−1, we recorded a higher draught rate at the ankle level, ranging from 6.55% to 9.99%. The lower equivalent temperature values for the foot and calf segments occur when the floor temperature is 20°C. In all cases, the equivalent temperature values of the whole body indicate an acceptable level of thermal discomfort.

Experimental study on thermal performance of roof and floor capillary radiant heating systems

This research picks up the bedroom and study of a residential building in Chengdu as the research object. The temperature variations in the supply water of the room, the surface temperature of roof and floor, and the indoor air is analysed when the capillary ends were located on the roof and the floor respectively. Furthermore, the internal mechanism of the different heating environments of the two heating modes is revealed by analysing the heat flux density. The results show that: under the same water supply temperature and flow rate, the thermal response time of the roof radiant heating is shorter and the stability of the surface temperature of the floor radiant heating is better due to the different thickness of the capillary network. The floor heating room has more uniform distribution and better comfort. The heat transfer characteristics of the roof and floor surface are different, and the variation of the radiation and convection heat transfer amount are also different. The heat flux density of the roof increases faster and the maximum value can be reached in only 60 minutes, while the floor needs 156 minutes. The roof heating is about 4.36% higher than the floor heating in the proportion of radiation heat exchange. Thus, roof radiant heating is preferred for intermittent heating. This paper provides a reference when designing the end of the residential heating systems.

Transient simulation study of floor heating systems

This case study is aimed at transient simulation of floor heating systems. There is comparison of surface floor temperatures and heat fluxes changes of different systems over time. The first studied system is a dry floor heating system which consists of system boards made from insulation material, spreader plates, and it is covered by cement fiber boards. The second examined system is heavy wet concrete floor heating system whose heating power is set identically as heating power of dry floor heating system. Mean temperature of heating water is investigated. All simulations, both time steady-state and transient, are performed in software CalA. Reduction of duration and computational performance of simulation is achieved by creation of a surrogate model. The surrogate model evinces identical surface temperatures and heat fluxes. Total number of computational grid is reduced and therefore lower number of equations is solved. Results show that dry floor heating system has faster response than concreate floor heating system. It is caused by lower weight and lower thermal capacity of this system.

Design and analysis of phase change material based floor heating system for thermal energy storage

Pleasant interior space is essential for modern people who spend considerably more time in the buildings than they did in the past. To achieve this, one aspect includes an ambient temperature that maintains the thermal equilibrium of the human body. The construction of wood framed buildings is becoming increasingly popular worldwide, and there have been recent trends toward constructing high-rise wooden houses. In this respect, heating methods appropriate for use in wooden buildings are being studied. Dry floor heating systems are predominantly used in wooden houses, but they provide a poor heat storage performance, which is not conducive to saving energy. In this study, the effects of thermal comfort and energy savings were analyzed after applying a phase change material (PCM) to floor heating, which can be used to reduce the peak temperature and contribute to energy savings. To enable shape stabilization, this study used Macro-Packed PCM (MPPCM), as shape stabilization is necessary when applying PCM. The heat storage performance was improved by applying MPPCM to a dry floor heating system. Paraffin-based PCMs, such as n-octadecane, n-eicosane, and n-docosane, were used to obtain a comfortable floor temperature range. Experimental temperatures ranged from 28 °C to 35 °C, with an entire temperature range of 7 °C. Experimental results showed that the heat storage performance of MPPCM reduced the amount of energy used for heating by 43%, and n-eicosane was the most effective PCM for use in floor heating with respect to obtaining a comfortable floor temperature.

Study on indoor comfort of floor radiant cooling and displacement ventilation system in large space

Radiant cooling and displacement ventilation system has an extensive application in large space building where there has a significant stratification of heat and mass. This paper focuses on the effects of the floor cooling proportion on the indoor comfort under radiant cooling and displacement ventilation system in large space. By simplifying the building model according to a practical waiting hall in certain railway station, a three-dimensional space model describing the comfort distribution characteristics in working area with composite system is presented. The discrete ordinates radiation model and indoor zero equation model are used to describe the indoor temperature and humidity distribution law. Floor temperature, inlet parameters and the indoor comfort control conditions are researched. The indoor thermal and moist environment is analyzed based on CFD simulation. The simulation results provide that the temperature and velocity of supply air had similar influencing characteristic on the indoor comfort. Meanwhile, the cooling capacity of floor could be higher when the supply air temperature was higher and the air supply velocity was lower and the optimum cooling proportion of floor was 0.76 to 0.77 in this paper. More importantly, the compound system could be applicable in indoor comfort control in large space.