scholarly journals Efficiency in Heating Operation of Low-Temperature Radiant Systems Working under Dynamic Conditions in Different Kinds of Buildings

2018 ◽  
Vol 8 (12) ◽  
pp. 2399 ◽  
Author(s):  
Giulia Alessio ◽  
Michele De Carli ◽  
Angelo Zarrella ◽  
Antonino Di Bella
Keyword(s):  
Heat Pump ◽  
Variable Temperature ◽  
Thermal Inertia ◽  
Energy Performance ◽  
Outdoor Temperature ◽  
Dynamic Conditions ◽  
Control Efficiency ◽  
Floor Systems ◽  
And Control ◽  
Better Than

In recent years many types of radiant systems have been installed in buildings. Meanwhile, practitioners debate on which thermal inertia of radiant systems fit better and which control strategies should be better in buildings, depending on the insulation level and thermal inertia of the structures. In particular, in new and retrofitted buildings, where the envelope presents high levels of insulation, it is argued if it is better to have low or high inertia radiant systems for controlling the indoor operative temperature and avoid overheating, especially in mid-seasons when the outdoor temperature is mild and solar radiation is high. For this purpose a room with three types of insulation level has been analysed combining different types of structures (masonry, and light and timber walls) and three types of radiant systems (classic wet floor, dry floor, and ceiling). Two operation modes have been simulated: fixed supply temperature and variable temperature according to the outdoor temperature. The results looked at the embedded and control efficiency, the energy performance in case of coupling with a water to water heat pump and the long-term possible overheating analysis. The embedded and control efficiency in dynamic conditions has been evaluated and compared with different possible definitions, in particular with steady state conditions, former EN15316-2-2007, and current EN15316-2-2017. New values for the current standard are suggested based on the results of this work, since the former and existing values overestimate the seasonal losses of floor and radiant systems in heating conditions. The paper shows that working at variable temperature according to the outdoor air temperature leads to longer operation time. The temperature, on average, lowers, and coupling the radiant system with a water to water heat pump leads to lower consumptions in the case of variable supply temperature compared to fixed supply temperature over the season. The seasonal coefficient of performance of the whole system, i.e. the heat pump and auxiliary pumps, leads to overall lower energy consumption in the case of variable supply temperature. The simulations did not show any relevant problem of discomfort from December to February. Overtemperature effects in terms of operative temperatures over the dead band of the control systems are not especially due to the radiant system, but they also occur in any case with ideal convective systems. The paper demonstrates that in general the radiant floor systems perform better than radiant ceilings in heating conditions and there is no evidence that dry floor systems perform better than wet screed systems in all the types of buildings regardless of the level of insulation and thermal inertia.

scholarly journals The Role of Emitters, Heat Pump Size, and Building Massive Envelope Elements on the Seasonal Energy Performance of Heat Pump-Based Heating Systems

Energies ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 5098
Author(s):  
Matteo Dongellini ◽  
Paolo Valdiserri ◽  
Claudia Naldi ◽  
Gian Luca Morini
Keyword(s):  
Energy Consumption ◽  
Heat Pump ◽  
Numerical Study ◽  
Thermal Inertia ◽  
Heating System ◽  
Energy Performance ◽  
Building Envelope ◽  
Control Logic ◽  
Pump System ◽  
Heat Pump System

The influence of emitters, heat pump size and building envelope thermal inertia was investigated on the energy consumption of a heat pump-based heating system with a numerical study performed with the dynamic software TRNSYS. An algorithm based on a Thermal Inertia Control Logic (TICL), which can exploit the capability of the building envelope to store thermal energy, has been applied. When the proposed algorithm is employed, the indoor air temperature set-point is increased when the outdoor temperature is larger than the bivalent temperature of the building-heat pump system. Different configurations of the heating system were simulated considering either convective (fan-coil) or radiant (radiant floor) emitters coupled to a variable-speed air-to-water heat pump. Simulations have been carried out considering a reference building derived from the IEA SHC Task 44 and evaluating the influence of the proposed control logic on both the heat pump seasonal energy performance and the internal comfort conditions perceived by the building users. The obtained results highlight how the introduced TICL can guarantee the use of downsized heat pumps, coupled to radiant emitters, with a significant enhancement of the seasonal performance factor up to 10% and a slight improvement of comfort conditions. On the other hand, when convective terminal units are considered the proposed logic is not effective and the overall energy consumption of the system increases up to 15%.

Clogging Problems in Groundwater Heat Pump Systems in Sweden

1988 ◽  
Vol 20 (3) ◽  
pp. 133-140 ◽  
Author(s):  
Annika Lindblad-Påsse
Keyword(s):  
Redox Potential ◽  
Heat Pump ◽  
Hydrogen Sulphide ◽  
Sludge Formation ◽  
Iron Bacteria ◽  
Iron Precipitation ◽  
Water Composition ◽  
Groundwater Heat Pump ◽  
And Control ◽  
System Knowledge

A number of groundwater heat pump systems have been investigated to determine the extent of problems caused by the chemistry of the groundwater used. The main purpose was to investigate sites using iron rich groundwater. Fifteen facilities were studied regularly for three years. Ten of these facilities had some kind of problem caused by iron precipitation. Four of the sites were rebuilt because of severe plugging due to iron sludge in wells, pumps and pipes. In all facilities with severe problems, iron bacteria were found. Low redox potential, indicated by hydrogen sulphide in the groundwater, seems to protect from iron bacteria. In some of the systems using groundwater with H2S the problems were corrosion and sludge formation caused by sulphur oxidizing bacteria. Rapid clogging was caused by aeration of the groundwater due to improper design of the system. Knowledge of the water composition, design of the systems to minimize aeration, and control of clogging turned out to be important factors to maintain operation safety.

Structure and control co-optimization for an ejector expansion heat pump coupled with thermal storages

2021 ◽  
Vol 235 ◽  
pp. 110755
Author(s):  
Fang Liu ◽  
Jiaxin Deng ◽  
Qiu Mo ◽  
Yanping Xu ◽  
Dan Liu ◽  
...  
Keyword(s):  
Heat Pump ◽  
And Control

HIEQ LAB: A NOVEL FULL-SCALE FACILITY WITH OCCUPANTS TO INVESTIGATE INTEGRATIVE LIGHTING AND HUMAN PERFORMANCE IN A MULTI-DOMAIN APPROACH

2021 ◽  
Author(s):  
L. Giovannini ◽  
V.R.M. Lo Verso ◽  
F. Favoino ◽  
V. Serra ◽  
A. Pellegrino
Keyword(s):  
Human Performance ◽  
Well Being ◽  
Energy Performance ◽  
Real Space ◽  
Indoor Environmental Quality ◽  
Design Strategies ◽  
Main Research ◽  
Building Components ◽  
Lighting Systems ◽  
And Control

The new HIEQ Lab (Health, well-being and Indoor Environmental Quality Laboratory) is presented. It is a living lab, primarily intended for research on human performance, comfort, and well-being, integrated with the energy performance in a completely controlled real space. Users are involved as active players in controlling and assessing building components and design strategies for health, well-being and IEQ requirements. Experimental activities will be addressed through a multi-domain approach that combines lighting, acoustic, air quality and thermal issues. For what concerns lighting, the laboratory is conceived to study the performance of daylighting and electric lighting systems and control solutions, focusing on the relationship between lighting conditions and human performance, comfort, and well-being. The paper reports the results of a literature review on existing lighting research facilities, and then describes the features of the new HIEQ Lab and its main research objectives, with a focus on lighting and daylighting research opportunities.

scholarly journals New Cancer Stochastic Models Involving Both Hereditary and Nonhereditary Cancer Cases: A New Approach

2013 ◽  
Vol 2013 ◽  
pp. 1-19
Author(s):  
Wai-Yuan Tan ◽  
Hong Zhou
Keyword(s):  
Cancer Incidence ◽  
Stochastic Models ◽  
Biological Information ◽  
Cancer Genes ◽  
New Approach ◽  
Human Cancers ◽  
Seer Data ◽  
Sampling Procedures ◽  
And Control ◽  
Better Than

To incorporate biologically observed epidemics into multistage models of carcinogenesis, in this paper we have developed new stochastic models for human cancers. We have further incorporated genetic segregation of cancer genes into these models to derive generalized mixture models for cancer incidence. Based on these models we have developed a generalized Bayesian approach to estimate the parameters and to predict cancer incidence via Gibbs sampling procedures. We have applied these models to fit and analyze the SEER data of human eye cancers from NCI/NIH. Our results indicate that the models not only provide a logical avenue to incorporate biological information but also fit the data much better than other models. These models would not only provide more insights into human cancers but also would provide useful guidance for its prevention and control and for prediction of future cancer cases.

scholarly journals THE EFFECTIVENESS OF REALISTIC MATHEMATICS EDUCATION TO IMPROVE STUDENTS’ MULTI-REPRESENTATION ABILITY

2019 ◽  
Vol 8 (1) ◽  
pp. 21 ◽  
Author(s):  
Muhtarom Muhtarom ◽  
Nizaruddin Nizaruddin ◽  
Farida Nursyahidah ◽  
Nurina Happy
Keyword(s):  
Mathematics Education ◽  
Experimental Design ◽  
Learning Process ◽  
Realistic Mathematics Education ◽  
Student Responses ◽  
Realistic Mathematics ◽  
Quasi Experimental ◽  
And Control ◽  
Essay Test ◽  
Better Than

This research aimed to evaluate the effectiveness of Realistic Mathematics Education (RME) to improve students' multi-representation ability. A quasi-experimental design was used in this research. Sixty-four samples from the seventh-grade students of Junior School were randomly selected and divided into two classes: experimental class was treated using RME and control class was treated using conventional learning, with each class consisting of thirty-two students. The essay test was used to measure the multi-representation ability of students and the questionnaire was used to measure students' responses in RME learning. The data from the essay test were analyzed by N-Gain test and t-test in which normality and homogenity test were conducted previously, while the students' learning completeness and student responses were presented descriptive quantitative. The result of the research concluded that the multi-representation ability of students who get RME learning is better than the multi-representation ability in students who get conventional learning. 87.25% of students who get RME learning with the developed device have completed the KKM, and many students are very enthusiastic and interested in RME based learning, thus increasing their learning spirit in a learning process.

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