► Hydronic radiant cooling is an alternative to conventional air-conditioning system. ► Condensation is the great challenge for chilled ceiling panels in hot humid climate. ► Desiccant dehumidifier ...reduces energy consumption and improves indoor air quality. ► Reactivation is the main limitation of desiccant dehumidification system. ► Relative humidity at 50% and 60%, allows chilled ceiling to be in save operation.
Experimental investigations were carried out to determine the performance of a rotating desiccant wheel with chilled ceiling panels for humid climates in Malaysia. Dehumidification capacity was in the range of 0.89–2.673kg/h. Relative humidity reduction to 40% with high dehumidification capacity of 2.673kg/h was achieved within 10min with air flow rate of 243kg/h. Chilled ceiling surface temperature between 14 and 18°C was achieved by varying the chilled water inlet temperature from 6°C to 10°C at steady state. Condensation was absent on the chilled ceiling surface panels below 70% relative humidity. Thermal comfort room temperature for this investigation was 24–24.5°C for chilled ceiling height of 2m.
•The HAMP is able to control the space humidity within specified control limits.•It directly responds to space latent loads and thus provide better humidity control.•Good potential for the RCP system ...with the HAMP to reduce the total energy consumption in buildings.•Energy is reduced by this system in the hot climates by 40% in Miami.•Energy is reduced by this system in the cold climates by 23% in Chicago.
Radiant panel systems have one of the highest technical energy savings compared to other HVAC systems and they achieve high comfort levels. However, they are unable to maintain the indoor relative humidity as they only transfer sensible heat. In order to overcome this problem, a novel heat and moisture transfer panel (HAMP) is developed and tested. In this paper, the applicability of the HAMP is tested using the TRNSYS simulation program. The impact of the HAMP on space relative humidity is investigated by modeling a one-storey office building in four North American cities (Chicago, Miami, Phoenix, and Saskatoon) as representatives of four major climatic conditions. The validity of the HAMP and resulting energy savings is represented and compared against the same building operating with two other HVAC systems: a conventional all-air system and a radiant ceiling panel (RCP) system with 100% outdoor air. The HAMP is able to control the relative humidity in the building between 25% RH and 60% RH in Chicago, Saskatoon, and Phoenix, and between 40% RH and 62% RH in Miami. The results also show the potential of the RCP system with the HAMP to reduce the total energy consumed by the conventional all-air system in different climates.
Well known in the North of Europe, the water ceiling panel systems are mainly used to provide cooling. However, as well as for a radiant floor, this system can be used for heating in winter and ...cooling in summer. In order to get a better knowledge of the energy performances of such devices, the Gaz de France Research Centre funded a test campaign during two winters and one summer. This experimental study was carried out in our laboratory, located in Rennes, in western France. A water ceiling panel system and a monitory data acquisition system were installed in a test room. The studied ceiling panel system was made of copper pipes with rigid aluminium diffusion fins. The used materials presented a good heating conductivity and the ceiling radiant panel was fast-acting.
Simulation models were developed with the simulation program TRNSYS, using the experimental study results for the code verification.
U radu su analizirani novi nalazi renesansnih drvenih stropova u palači Petris-Moise u Cresu ukrašeni oslikanim pločicama i zidni oslici. Elementi konstrukcija tehnički su sofisticirani, izrađeni ...sukladno renesansnim traktatima o arhitekturi, primjerice kompozitna masivna greda tzv. trave leonardesca. Oslikane stropne pločice po načinu ugradnje i oslikavanja za sada su jedinstven nalaz na području Hrvatske, ali su srodne brojnim ciklusima oslika na stropnim pločicama iz razdoblja od 14. pa do polovice 16. stoljeća u plemićkim rezidencijama južne Francuske, Španjolske, Švicarske i sjeverne Italije. Po dimenzijama, korištenim pigmentima, načinu ugradnje i slikanja te zastupljenim motivima najsličnije su primjerima iz Furlanije. Razlika je u tome što creski primjeri skoro u cijelosti pripadaju likovnom jeziku groteski jer nastaju nešto kasnije, u vrijeme pune afirmacije te vrste dekorativnog repertoara. Konstrukcije i dekorativni elementi pripadaju renesansnoj pregradnji iz druge polovice 16. stoljeća kada su oslikani i zidovi. Temeljem analize grbova i zastupljenih motiva te usporedbe s povijesnim podacima o članovima obitelji Petris identificiran je naručitelj, carski zlatni vitez Ivan Juraj Petris, bliski rođak Frane Petrisa, a iznesena je i pretpostavka kako je ciklus oslika nastao pod utjecajem tog znamenitog renesansnog filozofa.
Radiant ceiling panels are preferred over all-air systems because of their ability to lower energy consumption and maintain better comfort conditions. One disadvantage is their inability to moderate ...indoor humidity. To overcome this limitation, a new panel that can transfer heat and moisture is being developed. This research determines the performance of this panel under different temperature and humidity conditions. The effectiveness of the panel ranges from 15% to 28%, depending on the conditions. A computational fluid dynamics model of the panel has been developed using the commercial software, FLUENT. Good agreement is seen between experiments and the model for most cases. Comparing the change in humidity ratio of the air, the average difference is 5%.
In order to achieve significant savings in energy and an improved level of thermal comfort in retrofitted existing buildings, specific retrofitting concepts that combine new technologies and design ...need to be developed and implemented. Large radiant surfaces systems are now among the most promising future technologies to be used both in retrofitted and in new low-energy buildings. These kinds of systems have been the topic of several studies dealing with thermal comfort and energy utilization, but some specific issues concerning their possible use in various concepts for retrofitting are still poorly understood. In the present paper, some results of dynamic simulations, with the transient system simulation tool (TRNSYS) model, of the retrofitted offices equipped with radiant ceiling panels are presented and thoroughly analysed. Based on a precise comparison of the results of these simulations with actual measurements in the offices, certain input data for the model were added, so that the model was consequently validated. The model was then applied to the evaluation of various concepts of building envelopes for office retrofitting. By means of dynamic simulations of indoor environment it was possible to determine the benefits and limitations of individual retrofitting concepts. Some specific parameters, which are relevant to these concepts, were also identified.
Recent developments have prompted a review of evaporative cooling technology as an effective means of cooling modern deep plan buildings. Prominent among these developments is the success of high ...temperature sensible cooling systems, particularly, chilled ceilings, which require a supply of cooling water at 14–18
°C. Crucial to the success of evaporative cooling technology, as a significant means of cooling in modern applications, is the ability to generate cooling water, in an indirect circuit, at a temperature which closely approaches the ambient adiabatic saturation temperature (AST) or wet bulb temperature (WBT). Recent experimental research has demonstrated that it is technically viable to generate such cooling water at a temperature of 3
K above the ambient AST.
While the frequency of ambient AST occurrence can be obtained from meteorological sources, there is little in-depth analysis of the potential for this form of cooling water generation, based on the approach temperatures which have now been shown to be viable. The decision to use an evaporative cooling system depends largely on an assessment, in-depth, of net energy saved against capital expended. Such an assessment requires detailed data on the availability of cooling water, generated by evaporation, for each location. This paper quantifies evaporative cooling availability in-depth for a northern and southern European city, Dublin and Milan and suggests a method of analysing such data for any world wide location, for which suitable meteorological records are available. The paper, incorporates recent experimental research findings and bases the availability analysis on meteorological test reference weather year data.
The results of this research confirm a major potential for the generation of cooling water by evaporative means, which can be used to provide effective cooling of deep plan buildings by means of contemporary water based sensible cooling systems, such as fan coil systems, radiant chilled ceiling panels and ceiling cooling convectors (chilled beams). While the technique offers most potential in locations with a northern European temperate climate, it has significant potential to contribute to cooling in some southern European cities, during the non-summer months and also at other times, particularly where load shaving techniques are incorporated.
Radiant ceiling panels can be used in large-volume halls, e.g. vehicle repair shops and markets, to heat the entire or specific zones of the enclosed space. The system with radiant panels may be of ...small water capacity when just one or several units are installed over selected zones to provide additional heating. Depending on dimensions of radiant ceiling panel, its mounting mode and the temperature of its feeding medium, various thermal conditions are created under such panel. Thermal effects are also affected by the mode of thermal or cooling power control and dynamics of such control for an individual radiant panel or a set of panels. The dynamics of attainable radiant ceiling panel capacity was investigated and used as the grounds to determine general requirements for time-domain automatic control programs and those for operation of the controllers. The results presented from the examinations carried out for water radiators are not intended to delineate the requirements for all automatic control loops for water radiators; they are aimed at attracting attention to issues to be considered when preparing the algorithm of automatic control in particular situations.
Background
This study concerns the analysis of four painted wooden panels from the second half of the 15
th
century which embellish the ceiling of a palace situated in Cremona (Northern Italy). This ...type of painting was generally used to decorate the top of the walls and the ceilings of the rooms in aristocratic palaces and they usually portray the owner’s ancestors, family members or important visitors. The paintings are of historical importance since they enable us to study the clothing and hair styles which were in fashionable in Italy during the Renaissance. These panels were heavily damaged and required a lot of restoration including the cleaning of the paint layers. This enabled us to carry out a thorough examination of the materials and techniques used for creating these paintings.
Results
Various micro-samples were taken in order to distinguish the materials and, in particular: (i) to analyze the ground layer and study its function; (ii) to typify the organic binders and the pigments of the polychrome films. The stratigraphic sequence of micro-samples was analyzed using optical microscopy, the elemental composition was determined by means of the SEM-EDX technique while the organic binders were analyzed by means of μFT-IR spectroscopy. The main component of ground layer proved to be clay. The organic binder was probably composed of a protein-based material such as animal glue. This type of ground layer is similar to the traditional 15
th
century Flemish formula and seems to confirm the strong influence of that artistic technique in Northern Italy. Cross-section investigation showed a primer layer over the ground layer made of white lead pigment. In fact, a white primer was used to cover the ground layer of yellowish clay common in Central Europe. The importance of this research is also confirmed by the study of paint films, for which pigments such as azurite or cinnabar were used. Red lake pigment for painting the subjects’ complexions was emphasized.
Conclusions
The analyses provide new detailed information concerning the materials used for painting the ceiling panels, the layer sequence of the paints and Northern Italian 15
th
century painting techniques.
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