Experimental investigation on model predictive control of radiant floor cooling combined with underfloor ventilation system

Zhang, Dongliang; Cai, Ningsheng; Cui, Xiaobo; Xia, Xueying; Shi, Jianghong; Huang, Xiaoqing

doi:10.1016/j.energy.2019.03.102

Cited by 39 publications

(7 citation statements)

References 26 publications

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“…The hollow blue dots in series 1 denote non-compliance, i.e., cases where the operative temperature was greater than or equal to 20 • C for fewer than 14 h. The lowest thermal resistance value was recorded for the granite floor coverings, while all the other dots plot the findings for the dwellings with wood coverings. The effect of wood-covering thermal resistance on start-up lag time is plotted in Figure 16. In this figure, the points on the series 1 curve represent a given dwelling that, at the appropriate thermal resistance, takes the longest, in number of hours, to raise the operative temperature to 20°; the points on the series 2 curve represent the dwellings taking the least time at each thermal resistance.…”

Section: Effect Of Wood Thermal Resistancementioning

confidence: 99%

“…Numerous investigations have been carried out on the thermal performance of radiant floors from different perspectives, such as control [13,[16][17][18], thermal inertia [19,20], the use of PCMs [21][22][23][24][25][26][27], the arrangement of tubes [23,28], and the most suitable radiant surfaces [6], but fewer publications has been found on the influence of floor coverings properties, although, as Sattari and Farhanieh [29] showed in a parametric study, the thickness and thermal properties of the finish or covering have a major bearing on the performance of radiant floor heating.…”

Section: Introductionmentioning

confidence: 99%

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Influence of Wood Properties and Building Construction on Energy Demand, Thermal Comfort and Start-Up Lag Time of Radiant Floor Heating Systems

et al. 2022

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Radiant floor heating is becoming increasingly popular in cold climates because it delivers higher comfort levels more efficiently than conventional systems. Wood is one of the surface coverings most frequently used in radiant flooring, despite the widely held belief that in terms of thermal performance it is no match for higher conductivity materials if a high energy performance is intended. Given that the highest admissible thermal resistance for flooring finishes or coverings is generally accepted to be 0.15 m2K/W, wood would appear to be a scantly appropriate choice. Nonetheless, the evaluation of the thermal performance of wooden radiant floor heating systems in conjunction with the building in terms of energy demand, thermal comfort, and start-up period, has been insufficiently explored in research. This has led to the present knowledge gap around its potential to deliver lower energy consumption and higher thermal comfort than high-thermal-conductivity materials, depending on building characteristics. This article studies the thermal performance of wood radiant floors in terms of three parameters: energy demand, thermal comfort, and start-up lag time, analysing the effect of wood properties in conjunction with building construction on each. An experimentally validated radiant floor model was coupled to a simplified building thermal model to simulate the performance of 60 wood coverings and one reference granite covering in 216 urban dwellings differing in construction features. The average energy demand was observed to be lower in the wood than in the granite coverings in 25% of the dwellings simulated. Similarly, on average, wood lagged behind granite in thermal comfort by less than 1 h/day in 50% of the dwellings. The energy demand was minimised in a significant 18% and thermal comfort maximised in 14% of the simulations at the lowest thermal conductivity value. The vast majority of the wooden floors lengthened the start-up lag time relative to granite in only 30 min or less in all the dwellings. Wood flooring with the highest thermal resistance (even over the 0.15 m2K/W cited in standard EN 1264-2) did not significantly affect the energy demand or thermal comfort. On average, wood flooring lowered energy demand by 6.4% and daily hours of thermal comfort by a mere 1.6% relative to granite coverings. The findings showed that wood-finished flooring may deliver comparable or, in some cases, higher thermal performance than high-conductivity material coverings, even when their thermal resistance is over 0.15 m2K/W. The suggestion is that the aforementioned value, presently deemed the maximum admissible thermal resistance, may need to be revised.

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Section: Effect Of Wood Thermal Resistancementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Influence of Wood Properties and Building Construction on Energy Demand, Thermal Comfort and Start-Up Lag Time of Radiant Floor Heating Systems

et al. 2022

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“…Underfloor cooling has been the object of intense research due to the structural similarity and operation with underfloor heating [16] but also due to condensation risk and low cooling capacity [17]; moisture condensation at the floor surface is usually avoided by supplying conditioned dry air within ventilation ducts [18]. All in all, research papers on this topic are quite numerous, ranging from the implementation of phase-change materials (PCM) into the system design [19] to thorough testing of the heat-transfer process occurring over the floor surface [20].…”

Section: Introductionmentioning

confidence: 99%

Cooling Thermal Comfort and Efficiency Parameters of Ceiling Panels, Underfloor Cooling, Fan-Assisted Radiators, and Fan Coil

2022

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Climate change has brought a compelling need for cooling living spaces to the attention of researchers as well as construction professionals. The problem of overheating enclosures is now exacerbated in traditionally affected areas and is also affecting countries that were previously less prone to the issue. In this paper, we address measurements of thermal comfort and cooling emission efficiency parameters for different devices: ceiling panels, underfloor cooling, fan-assisted radiators, and fan coil. These devices were tested in low and high cooling capacities of up to 40 W/m2 while also featuring heating dummies to imitate internal heat gains. Air temperatures were measured at different heights, allowing to evaluate the thermal stratification with high accuracy. Thermal comfort differences of the tested systems were quantified by measuring both air velocities and operative temperatures at points of occupancy. In summary, the best-performing cooling devices for the studied cooling applications were the ceiling panels and fan radiators, followed by underfloor cooling, with a limitation of stratification. Because of the strong jet, fan coil units did not achieve thermal comfort within the whole occupied zone. The results can be utilized in future studies for cooling emission efficiency and energy consumption analyses of the different cooling devices.

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“…To improve the thermal performance of radiant floors, several research studies have focused on construction types [11][12][13][14] and control-related factors [13,[15][16][17][18][19][20][21] such as response time [15] and the inclusion of phase change materials [22][23][24][25]. Specifically, some authors have studied the effect of the thermal conductivity of wood on radiant floor heating systems [26] and ways to improve its performance, focusing on reducing the thermal resistance between the water pipes and interior space by means of different installation methods [27] or by improving the thermal conductivity of the floor covering itself [28].…”

Section: Introductionmentioning

confidence: 99%

Effect of Wood Properties and Building Construction on Thermal Performance of Radiant Floor Heating Worldwide

et al. 2022

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Due to its relatively lower thermal conductivity, the suitability of wood is called into question when selecting the flooring material best suited to radiant heating systems. The European standard EN 1264 considers floorings with a thermal resistance over 0.15 m2 K/W to be out of scope. This belief was partially disproved in a previous article that studied wooden floors for Madrid’s climate. However, the effect of climate still needs to be addressed. The present study extends the previous research to worldwide climates and aimed to answer the following questions: (1) Do the lowest thermal conductivity woods present good thermal performance when used in radiant floors? (2) Should the flooring have a maximum thermal resistance value? (3) Is the standard thermal resistance limit of 0.15 m2 K/W objectively justified? And (4) Do the answers of the preceding questions depend on the climate and the construction characteristics? To answer these questions, 28 cities were selected according to the Köppen–Geiger climate classification. In each city, 216 different dwellings were simulated with 60 wood floorings and one of low thermal resistance as a reference, comprising a total of 368,928 cases. Thermal performance was evaluated in terms of three parameters: energy demand, thermal comfort, and start-up lag time. Consequently, the answers to the previous questions were: (1) The lowest thermal conductivity woods can be used efficiently worldwide in radiant floor heating systems with start-up lag times close to that of the reference flooring; (2) There is no limit value for thermal resistance for floorings that can be applied to all dwellings and climates; (3) No objective justification was found for establishing a thermal resistance limit for flooring of 0.15 m2 K/W; and (4) Climate and construction characteristics can play an important role in the correct selection of flooring properties, especially in severe winters and dwellings with the greatest outdoor-exposed envelope and the worst insulation.

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Experimental investigation on model predictive control of radiant floor cooling combined with underfloor ventilation system

Cited by 39 publications

References 26 publications

Influence of Wood Properties and Building Construction on Energy Demand, Thermal Comfort and Start-Up Lag Time of Radiant Floor Heating Systems

Influence of Wood Properties and Building Construction on Energy Demand, Thermal Comfort and Start-Up Lag Time of Radiant Floor Heating Systems

Cooling Thermal Comfort and Efficiency Parameters of Ceiling Panels, Underfloor Cooling, Fan-Assisted Radiators, and Fan Coil

Effect of Wood Properties and Building Construction on Thermal Performance of Radiant Floor Heating Worldwide

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