scholarly journals CALCULATION METHOD OF CULTIVATION FACILITY COMBINED HEATING SYSTEM USING WINTER GREENHOUSE AS AN EXAMPL

2019 ◽  
pp. 47-55
Author(s):  
M. Pavlov ◽  
D. Karpov
Keyword(s):  
Air Temperature ◽  
Calculation Method ◽  
Heating System ◽  
Infrared Heating ◽  
Convective Heating ◽  
Mass Fluxes ◽  
Infrared Emitters ◽  
Form Design ◽  
Artificial Heating ◽  
Standard Values

Modern systems of artificial heating of cultivation structures on the example of winter greenhouses intended for year-round use require the development of sufficiently accurate and reliable methods of calculation. According to the calculations, a decentralized heating system of agricultural facilities, which includes only ceiling infrared heating elements, is justified only in a moderately cold period of the year. At lower outdoor temperatures, mainly in January, the indoor temperature may drop below standard values due to the specifics of radiant heating. Therefore, the article considers the method of calculating heat power of the radiant and convective heating system that includes infrared emitters for soil heating and convective heating devices for maintaining the target indoor air temperature. The calculation procedure of radiant and convective (combined) heating system comes to the calculation of incoming and outgoing heat and mass fluxes as well as finding unknown microclimate parameters (first of all, inside air temperature) that form design heat and humidity conditions of an agrobiotechnological facility. The proposed calculation method has been tested at the industrial greenhouse “Fermer 7.5”.

scholarly journals Energy Saving and Charging Discharging Characteristics of Multiple PCMs Subjected to Internal Air Flow

Fluids ◽  
2021 ◽  
Vol 6 (8) ◽  
pp. 275
Author(s):  
Ahmed J. Hamad
Keyword(s):  
Phase Change ◽  
Energy Saving ◽  
Air Temperature ◽  
Temperature Control ◽  
Phase Change Materials ◽  
Energy Savings ◽  
Heating System ◽  
Air Heating ◽  
Room Model ◽  
Model Temperature

One essential utilization of phase change materials as energy storage materials is energy saving and temperature control in air conditioning and indirect solar air drying systems. This study presents an experimental investigation evaluating the characteristics and energy savings of multiple phase change materials subjected to internal flow in an air heating system during charging and discharging cycles. The experimental tests were conducted using a test rig consisting of two main parts, an air supply duct and a room model equipped with phase change materials (PCMs) placed in rectangular aluminum panels. Analysis of the results was based on three test cases: PCM1 (Paraffin wax) placed in the air duct was used alone in the first case; PCM2 (RT–42) placed in the room model was used alone in the second case; and in the third case, the two PCMs (PCM1 and PCM2) were used at the same time. The results revealed a significant improvement in the energy savings and room model temperature control for the air heating system incorporated with multiple PCMs compared with that of a single PCM. Complete melting during the charging cycle occurred at temperatures in the range of 57–60 °C for PCM1 and 38–43 °C for PCM2, respectively, thereby validating the reported PCMs’ melting–solidification results. Multiple PCMs maintained the room air temperature at the desired range of 35–45.2 °C in the air heating applications by minimizing the air temperature fluctuations. The augmentation in discharging time and improvement in the room model temperature using multiple PCMs were about 28.4% higher than those without the use of PCMs. The total energy saving using two PCMs was higher by about 29.5% and 46.7% compared with the use of PCM1 and PCM2, respectively. It can be concluded that multiple PCMs have revealed higher energy savings and thermal stability for the air heating system considered in the current study.

Analysis of the influence of the internal heat capacity of the university building and weather-dependent regulation of itp on the efficiency of the heating system in standby mode

2021 ◽  
pp. 45-61
Author(s):  
I. Antypov ◽  
◽  
A. Mishchenko ◽  
O. Shelimanova ◽  
S. Tarasenko ◽  
...  
Keyword(s):  
Heat Capacity ◽  
Air Temperature ◽  
Internal Heat ◽  
Thermal Inertia ◽  
Heating System ◽  
Dynamic Mode ◽  
Temperature Deviation ◽  
Limit Value ◽  
Internal Heat Capacity ◽  
Standby Mode

When assessing the thermal condition of the building and the parameters of the microclimate of the premises, the main factors influencing its thermal inertia were identified and taken into account. An assessment of the influence of the resistance of enclosing structures on the efficiency of the heating system, taking into account the influence of external and internal climatic parameters in the dynamic mode. It is shown that the time factor and depth of regulation, as well as the outdoor air temperature are important factors. Researches are carried out and the expediency of introduction of a duty mode of heating of buildings of HIGH SCHOOLS is estimated. The given algorithm of control of process of heat release (especially in the presence of a point of "breaking" - average (them) on the schedule) in addition increases accuracy of the decisions of the specified problems and reduces a temperature deviation by 4 ÷ 6 ° C in comparison with usual ("linear") dependence that allows to correct more precisely release of the heat carrier in system of heating of a structure at introduction of a standby mode. It was found that it took about 6.5 hours to achieve normalized air temperature and space heating in the forced (after a long stay on duty). It is shown that the heat consumption of the system in such conditions of its operation compared to the nominal mode increased by 25 % (taking into account the limit value of the specific allowance from table H1 DBN B.2.5-67: 2013 "Heating, ventilation and air conditioning"), but for the entire period the action of the standby mode savings amounted to about 6-8% of energy consumed. Taking into account the design of the outer walls of the object of study, the temperature graph of the heating system was adjusted taking into account the value of the internal heat capacity of the building when implementing on-duty heating, which, according to preliminary estimates, will: improve comfort in the room; to reduce heating costs of the educational and administrative building of NULES of Ukraine by 10-12 % for the heating period. Key words: microclimate, internal heat capacity of a building, standby mode, heating system, heat loss

Contributions of Convective and Orographic Gravity Waves to the Brewer–Dobson Circulation Estimated from NCEP CFSR

2020 ◽  
Vol 77 (3) ◽  
pp. 981-1000
Author(s):  
Min-Jee Kang ◽  
Hye-Yeong Chun ◽  
Byeong-Gwon Song
Keyword(s):  
Gravity Waves ◽  
Mass Flux ◽  
Convective Heating ◽  
Flux Divergence ◽  
Mass Fluxes ◽  
Time Period ◽  
Physically Based ◽  
Total Mass Flux ◽  
Convective Gravity Waves

Abstract Contributions of convective gravity waves (CGWs) and orographic gravity waves (OGWs) to the Brewer–Dobson circulation (BDC) are examined and compared to those from resolved waves. OGW drag (OGWD) is provided by NCEP Climate Forecast System Reanalysis (CFSR), while CGW drag (CGWD) is obtained from an offline calculation of a physically based CGW parameterization with convective heating and background data provided by CFSR. CGWD contributes to the shallow branch of the BDC regardless of the season, while OGWD contributes to both the shallow and deep branches except for the summertime, when OGWs hardly propagate into the stratosphere. At 70 hPa, the annual-mean tropical upward mass fluxes from Eliassen–Palm flux divergence (EPD), OGWD, and CGWD are 68%, 7%, and 4% of the total mass flux, respectively. The tropical upward mass flux at 70 hPa shows an increasing trend during the time period from 1979 to 1998, with 28%, 18%, and 6% of the trend driven by EPD, OGWD, and CGWD, respectively. The width of the turnaround latitudes tends to narrow for the streamfunctions induced by OGWD and CGWD but tends to widen for that induced by EPD. The contributions of GWD from MERRA (MERRA-2) to the climatology and long-term trend of the BDC are 7% (7%) and 13% (4%), respectively, somewhat smaller than the contributions of CGWD plus OGWD, which are estimated from CFSR to be 12% and 20%, respectively.

scholarly journals Bioenvironmental Zonal Controlling of Incubated Avian Embryo Using Localised Infrared Heating

Processes ◽  
2019 ◽  
Vol 7 (10) ◽  
pp. 651 ◽  
Author(s):  
Youssef ◽  
Norton ◽  
Berckmans
Keyword(s):  
Air Temperature ◽  
Energy Use ◽  
Incubation Temperature ◽  
Living System ◽  
Radiative Heating ◽  
Infrared Heating ◽  
Reference Trajectory ◽  
Avian Embryo ◽  
Total Energy Consumption ◽  
Continuous Feedback

The main objective of any bioenvironmental controller is to create favourable bioenvironmental conditions around the living-system. In industrial incubation practice of chicken embryo, it is sometimes difficult to fill large incubators with uniform eggs, which leads to suboptimal results. The ideal incubation solution is a machine that is capable of coping with all sorts of variabilities in eggs. This can be realised in practice by creating different zones of different environmental conditions within the same machine. In the present study, a two-levels controller was designed and implemented to combine both convective and radiative heating to incubate eggs. On the higher level, three model-predictive-control (MPC) constrained controllers were developed to regulate the power applied to nine IR-radiators divided into three zones based on continuous feedback of the eggshell temperatures in each zone. On the lower level, a PID controller was used to maintain the air temperature within an experimental incubator at a fixed level (34 °C) lower than the standard incubation temperature. Four full incubation trials were carried out to test and implement the developed zonal controllers. The implementation results showed that the developed controllers were able to follow the reference trajectory defined for each zone. It was possible to keep the eggshell temperatures within the middle region (zone) different from the sidelong regions (zones) while the air temperature kept constant at 34 °C. The average hatching result (HOF) of the four full incubation trial was 84.0% (±0.5). The developed two-levels control system is a promising technique for demand-based climate controller and to optimizing energy use by using multi-objectives MPCs with constraint on total energy consumption.

scholarly journals Control, Regulation and Command System of Hydronic Radiant Floors Heating by Wireless and Energy Harvesting Sensors and Actuators

2013 ◽  
Vol 543 ◽  
pp. 389-392 ◽  
Author(s):  
Gilberto Batista ◽  
Pedro Dinis Gaspar ◽  
Pedro D. Silva
Keyword(s):  
Energy Harvesting ◽  
Thermal Comfort ◽  
Air Temperature ◽  
Heating System ◽  
Comfort Level ◽  
Sensors And Actuators ◽  
Control Regulation ◽  
Radiant Temperature ◽  
And Control ◽  
Actual Control

This paper presents the development of an innovative control, regulation and command system for hydronic radiant floors, more flexible and efficient that guarantees a better thermal comfort to the user and simultaneously improves the energy efficiency of this type of heating system. The majority of the actual control of hydronic radiant floors is done by thermostats that measure the air temperature and control the actuators (pumps and valves) in order to maintain the room at the specified temperature. These systems requires the frequent adjustment of thermostats set-point in order to obtain thermal comfort as it depends on other factors than just the air temperature, such as, the air humidity, external environmental conditions, radiant temperature, among others. This paper presents a control, regulation and command solution that requires minimum user intervention, as the user only has to choose the desirable thermal comfort level. The control algorithm is based on the calculation of PMV (Predicted Mean Vote) index as defined on Thermal Comfort Standard ISO 7730. Another advantage of the proposed system is related to the wireless and energy harvesting sensors and actuators that provide much more flexibility to the system.

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