scholarly journals Effects of Specific Parameters on Simulations of Energy Use and Air Temperatures in Offices Equipped with Radiant Heating/Cooling Panels

2019 ◽  
Vol 9 (21) ◽  
pp. 4609 ◽  
Author(s):  
Sabina Jordan ◽  
Jože Hafner ◽  
Martina Zbašnik-Senegačnik ◽  
Andraž Legat
Keyword(s):  
Simulation Model ◽  
Indoor Air ◽  
Energy Use ◽  
Small Degree ◽  
Radiant Heating ◽  
Feedback Information ◽  
Heating And Cooling ◽  
Air Temperatures ◽  
Frequency Magnitude ◽  
Real Building

When creating a simulation model to assess the performance of buildings, there is usually a lack of feedback information. Only in the case of measurements of a real building is a direct comparison of the measured values and simulated results possible. Parameter data related to users’ behavior or other events can also be obtained. Their evaluated frequency, magnitude and duration, along with boundary conditions, are crucial for the results. It is clear that none of them can be predicted very accurately. Most of them, however, are needed for computer modeling. In this paper we analyzed the well-defined TRNSYS simulation model of offices equipped with radiant ceiling panels for heating and cooling. The model was based on real case offices and was validated based on measurements for 1 year. The analysis included simulations in order to define what effect the parameters related mainly to users have on the energy use and the indoor air temperatures. The study confirmed that specific human activities influence the annual energy use to a relatively small degree and that their effects often counteract. It also confirmed the even more important fact that although small, these activities can influence the thermal comfort of users. It is believed that despite the fact that this research was based on an analysis of offices equipped with radiant ceiling panels, most of the results could be applied generally.

Simulating the Use of CO2 Concentration Inputs for Controlling Temperature in a Hydronic Radiant System

2017 ◽  
Author(s):  
Michael Sterman ◽  
Melody Baglione
Keyword(s):  
High Performance ◽  
Energy Use ◽  
Numerical Models ◽  
Co2 Concentration ◽  
Ann Model ◽  
Heating And Cooling ◽  
Air Temperatures ◽  
Demand Fluctuations ◽  
Carbon Dioxide Co2 ◽  
And Control

Incorporating predictive control into heating, ventilation and air conditioning (HVAC) systems has the potential to improve occupancy comfort and reduce energy use. This paper simulates the novel use of carbon dioxide (CO2) concentration inputs to augment temperature prediction and control. An artificial neural network (ANN) model and a least mean squares (LMS) filtering algorithm are used to simulate the temperature and control of a classroom in a high performance academic building with hydronic radiant heating and cooling panels. Numerical models are populated with variables that affect the heat energy entering, leaving, and being generated in a classroom. These variables include indoor and outdoor air temperature, radiant water and supply air temperatures, and classroom CO2 concentrations. The models are compared and then used to simulate the effect of a new control system that inputs CO2 measurements to account for the heat being generated by occupants of the controlled space. Simulation results suggest that augmenting HVAC control systems with CO2 measurements has the potential to improve temperature regulation by anticipating heating and cooling demand fluctuations in spaces with abrupt changes in occupancy.

THERMAL PERFORMANCE OF FELT TYPE VEGETATED FACADE SYSTEMS IN A TEMPERATE CLIMATE DURING HEATING AND COOLING PERIODS

2021 ◽  
Vol 16 (4) ◽  
pp. 199-225
Author(s):  
Elif Özer Yüksel ◽  
Nil Türkeri
Keyword(s):  
Thermal Performance ◽  
Indoor Air ◽  
Test Results ◽  
Exterior Wall ◽  
Exterior Surface ◽  
Existing Building ◽  
Cooling Period ◽  
Heating And Cooling ◽  
Surface Temperatures ◽  
Air Temperatures

ABSTRACT Using vegetated facade systems (VFS) as a sustainable solution for existing and new buildings and evaluating thermal performance of these sytems are not a new concept. However, there is a gap in literature about measuring thermal performance of VFS applied on an insulated wall. Also, in the research literature, there are few studies measuring thermal performance of felt type VFS in temperate climates, and data about the thermal performance of VFS during winter periods is still scarce. Thus, the aim of the present study is to measure the thermal performance of a felt type VFS applied on a thermal insulated existing wall that us located in Kocaeli, Turkey, under Csa climate conditions during heating and cooling periods. Test results indicate that the felt type VFS acts as a shading device and has a positive contribution to the thermal performance of building walls during a cooling period. In daytime when there is a high amount of solar radiation, felt type VFS decreased exterior surface temperatures of the insulated existing wall by a maximum of 24.4°C, 32.2°C and 37.2°C, in spring, summer and fall periods, respectively. Additionally, indoor air temperatures of the vegetated facade were lower than indoor air temperatures of the reference facade with the maximum difference of 1.8°C during the cooling period. Also, test results indicate that the vegetated facade never dropped to below 0°C while exterior surface temperatures of the reference facade dropped below 0°C at nighttime in the winter period. Thus, it can be claimed that the felt type VFS behaves as a thermal buffer and enhances the thermal performance of the exterior wall of the existing building during heating periods at nighttime. As a conclusion, although differences between exterior surface temperatures of vegetated and reference walls were high, differences between interior surface temperatures of vegetated and reference walls were not meaningful. That is due to the fact that the existing building exterior wall assembly includes 5 cm thickness thermal insulation material which enhance the thermal performance of the brick wall. Finally, according to solar reflectance results, it can be claimed that vegetated facade systems have a positive effect on reducing urban heat island effect.

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