Constructal Macroscale Thermodynamic Model of Spherical Urban Greenhouse Form with Double Thermal Envelope within Heat Currents

Abstract

Urban agriculture is becoming a timely environmental friendly practice to strengthen cities’ resilience to climate change. However, there is a lack of academic literature regarding the thermodynamic potential of interior urban agriculture. Furthermore, there is always a need to develop, from scratch, an updated methodological approach that aims to assist architects of conceiving such specific thermodynamically complex interior environments. In this paper, urban space is identified as a ‘flow system’, and Bejan’s constructal law of generation of flow structure is used to morph and discover the system flow architecture that offers greater global performance (greater access to what flows). More precisely, a macroscale thermodynamic model of spherical urban greenhouse form with double thermal envelope has been developed while the methodological approach resulted in the definition of a decisional flowchart that can be reproduced by other researchers. On the basis of this macroscale constructal model, the present paper proposes reduced models that link thermodynamic and geometric parameters in an accurate manner and can be used at early design stages for pedagogic and qualitative optimization purposes, integrating urban farming to architectural programming.

Compounds with Epoxy Resins and Phase Change Materials for Storage in Solar Applications

“…The configuration of the layers of the panel did not allow more alternatives than the defined one. However, if such a PCM were applied in other solutions, such as building envelopes, it should be selected based on tested methodologies [26]. Because the solar panel included a PCM composite layer with variable thermal conductivity, the conduction finite difference (CondFD) solution algorithm was employed as a heat balance algorithm.…”

Effective R-value approach to comprehend the essence of integrated opaque passive substrate properties

“…There is a need to formulate new expressions for dynamic effective thermal resistance increment (provided by the passive strategies) under transient weather conditions and incorporating into the existing codes, as discussed in [6][7][8]10]. Experimental [11][12] and numerical [13][14][15][16][17][18][19][20][21][22][23][24] studies on the effective thermal resistances due to various passive strategies such as green roof, ventilated roof and insulation roof were reported. However, the results of these studies are limited to specific building materials, wall configurations, indoor/outdoor boundary conditions etc., restricting their general applicability to integrated properties e.g., combination of cool coating with phase change material or air-cavities, as discussed in [16].…”

Effect of Particle Sizes of Nickel Powder on Thermal Conductivity of Epoxy Resin-Based Composites under Magnetic Alignment

“…To verify the effect of particle sizes of nickel powder on thermal conductivity of epoxy resin-based composites under magnetic alignment in Figure 5, the models of sample filled with different particle sizes of Ni were established in COMSOL software (COMSOL Inc., Stockholm, Sweden) [31][32][33]. Because the agglomeration phenomenon of nano-Ni powder is serious, it is difficult to simulate the agglomeration phenomenon in the model.…”