Renewable HVAC and Refrigeration Cycles

Future projections using climate models suggest an increase in the global annual average temperature of around 1.5-2 degrees Celsius by 2040. The impact of this increase will create socio-economic and safety challenges for all segments of society. In response to these challenges, several countries adopted various Climate Change Plans. The main framework of those plans involves, among other pillars, a two-pronged approach: (i) Climate change adaptation by increasing the flexibility in the decisions and activities toward the existing or expected changes in climate, and (ii) Climate change mitigation that aims to reduce and restrain greenhouse gases (GHG) emissions. Therefore, it is of great interest to incorporate renewable energy tactics as supplemental energy sources to lower the overall GHG emissions. 

The interest in using PCMs in passive latent heat thermal energy storage has been continuously growing in recent years. The PCMs provide a large heat capacity over a limited temperature range, making them one of the most suitable solutions to store large quantities of thermal energy. Despite the promising outcomes of using PCM as passive energy storage, almost all available PCMs share a common disadvantage: a relatively low thermal conductivity, which, in turn, limits their overall efficiency. Therefore, this part of my research will introduce a reliable, cost-effective method to overcome the low thermal conductivity drawback of the PCMs by utilizing additive manufacturing metallic materials. The fundamental notion behind this idea is to design an engineered 3D printed metal tank filled with a suitable PCM to supply cold-energy for air-conditioning applications without any use of batteries. In general, the principle of using PCMs within a porous metal matrix is a challenging fundamental problem; it is intrinsically a multi-physics process. It involves transient, multi-phase heat transfer, fluid mechanics, and solid mechanics of a porous periodic structure. Besides, it is a very delicate process because of its strong nonlinearity. 
Schematic diagram of an HVAC system equipped with a short term 3D printed storage tank filled with PCM.


Characterization of energy efficient vapor compression cycle prototype with a linear compressor

Mahmoud Alzoubi, Tiejun Zhang

International Conference on Applied Energy, (ICAE2015), Abu Dhabi, UAE, 2015

Investigation of two-phase frictional pressure drop and thermal entrance length in a minichannel helical heat exchanger

Charles Okaeme, Guanqiu Li, Mahmoud Alzoubi, Tiejun Zhang

ASME International Conference on Micro/Nanoscale Heat and Mass Transfer (MNHMT2013), Hong Kong, China, 2013

First-principle dynamic modeling of a linear micro-compressor

Mahmoud Alzoubi, Guanqiu Li, Tiejun Zhang

ASME International Mechanical Engineering Congress and Exposition (IMECE2013), San Diego CA, USA, 2013