Energy Savings of Simultaneous Heating and Cooling System According to Indoor Set Temperature Changes in the Comfort Range

This study was conducted to derive the amount of energy savings when applying the method of making the load similar by changing the set temperature of the room in the building to which the simultaneous heating and cooling (SHC) system is applied. Energy savings were derived through theoretical analysis and comparisons through static simulations were performed to verify the proposed method. As a result, the energy savings are proportional to the energy limit that can be additionally input to the SHC and is proportional to the ratio of the coefficient of performance (COP) difference between the SHC and auxiliary heat source and the auxiliary heat source COP. That is, to increase the amount of energy savings, the maximum possible energy should be input for the SHC, or the SHC COP must be greater than the auxiliary heat source COP. In addition, comfort can be achieved stably by varying the set room temperature in a room with a small load. When a heat storage tank is installed or changing the indoor set temperature of both the hot and cold zones in real time by predicting the indoor load is possible, more energy can be saved.

Magnetohydrodynamic bioconvection of oxytactic microorganisms in porous media saturated with Cu–water nanofluid

Purpose The purpose of this study is to address magnetohydrodynamic (MHD) bioconvection caused by the swimming of oxytactic microorganisms in a linearly heated square cavity filled with porous media and Cu–water nanofluid. The effects of different multiphysical aspects are demonstrated using local distributions as well as global quantities for fluid flow, temperature, oxygen concentration and microorganisms population. Design/methodology/approach The coupled transport equations are converted into the nondimensional partial differential equations, which are solved numerically using a finite volume-based computing code. The flow of Cu–water nanofluid through the pores of porous media is formulated following the Brinkman–Forchheimer–Darcy model. The swimming of oxytactic microorganisms is handled following a continuum model. Findings The analysis of transport phenomena of bioconvection is performed in a linearly heated porous enclosure containing Cu–water nanofluid and oxytactic microorganisms under the influence of magnetic fields. The application of such a system could have potential impacts in diverse fields of engineering and science. The results show that the flow and temperature distribution along with the isoconcentrations of oxygen and microorganisms is markedly affected by the involved governing parameters. Research limitations/implications Similar study of bioconvection could be extended further considering thermal radiation, chemical attraction, gravity and light. Practical implications The outcomes of this investigation could be used in diverse fields of multiphysical applications, such as in food industries, chemical processing equipment, fuel cell technology and enhanced oil recovery. Originality/value The insight of the linear heating profile reveals a special attribute of simultaneous heating and cooling zones along the heated side. With such an interesting feature, the MHD bioconvection of oxytactic microorganisms in nanofluid-filled porous substance is not reported so far.

MASTERPLANNER: A CENTRAL UTILITY PLANT DESIGN AND OPTIMIZATION TOOL

This paper presents a web-based software for designing optimal central utility plants. This tool can receive user-defined load profiles or generate typical load profiles based on user-specified combination and areas of 16 reference building types. The software then solves a linear-programming optimization comprising 8760 sets of equations and constraints to design central plant configurations with minimal first cost, operating cost, life-cycle cost, energy use, or marginal carbon emissions. The tool also calculates simultaneous heating and cooling loads to evaluate using heat-recovery chillers, and it can design both hot and cold thermal energy storage as well as water-side economizers.

Investigation on Mechanical Behavior of Sisal Fiber Reinforced Polylactic Acid and Sisal/Epoxy Composites

. Natural fibers have been found to be an alternative resource for synthetic materials. Natural composites are found to be a one hundred percent bio degradable product. Natural composites are also found to be having a great strength to weight ratio. In this process, hybrid sisal and polylactic bio composites are reinforced together by using the hand layup method. The ratio of sisal and polylactic element is in the ratio of 1:1 that are subjected to a compressive force with simultaneous heating process. Tensile strength and Flexural strength are evaluated as per the ASTM standards. Results shown that the there is good improvement in polylactic acid based biocomposite due to good interfacial between fiber and matrix.