Combustion characteristics and NOx emissions of propane and air mixture in a channel with a bluff body were investigated experimentally. Effects of the angle and type of the flameholder on the NOx emissions, blow-off limit, combustion efficiency, and exhaust gas temperature were examined. The results show that the NOx emissions are dependent on flameholder type and angle. Also it was observed that the perforated V-gutters considerably increases the blow-off performance. Moreover, the blow-off limit decreases as the geometrical size of flame-holder is increased. In addition, the combustion efficiency increase first and then decrease with the increase of the angle. The physics of the combustion process behind V-gutter flameholdes has been discussed. On the basis of experiment authors presented a modified version of the formula for calculation of lean blow-off limits when using bluff bodies, such as V-gutter flameholders.

Blow-off performance and NO x emissions of the propane and air mixture in a rectangular combustion chamber with bluff bodies were investigated experimentally and numerically. The effects of distance between bluff bodies on NO x emissions, the blow-off limit, and exhaust gas temperature were examined. It was observed that NO x emissions are highly dependent on distance between V-gutters. The re-circulation zone behind the bluff body expands in width based on the decrease of distance between V-gutters, and expands in length with the increase of inlet velocity. The temperature fields behind the bluff body show a similar change, the temperature behind the bluff body reaches its highest when the distance between V-gutters reaches 20 mm, meaning it has better flame stability. The blow-off limit is significantly improved with the decrease of distance between V-gutters. The blow-off limit is greatly improved by reducing the distance between the V-gutters. Maximum blow-off limit of 0.

Experiments on fuel effects flame stabilization processes, NOx generation and temperature at combustion chamber outlet when using a group of three V-gutter flame holders have been reported. Fuel supply directly to the re-circulation zone on the inside of the V-gutter (type A fuel supply), and alternatively in the second type, fuel was supplied to the V-gutter symmetry axis on the outside (type B fuel supply have been carried out.

As climate change concerns are rising rapidly, energy efficiency promotion and implementation could be sustainable solutions within energy transition. In this context, buildings, including educational ones, play an important role in reducing energy needs and promoting energy efficiency since they account for a significant share of the total energy consumption. As a case study for this research, the educational building of Kazakh-German University was selected. Following the national and international building standards, energy performance parameters were estimated. Current heat losses and performance have been estimated as baseline scenario settings. The impact of retrofitting measures on energy efficiency performance of the buildings under the four scenarios was calculated. Under the minor scenario, retrofitting interventions will lead to annual energy savings of 36.9 kWh/m2 and a 48% CO2 emission reduction, whereas under the major scenario, the annual energy savings will increase to 77.76 kWh/m2 and a nearly 82% CO2 emission reduction. The integration of a solar thermal system with capacity 400 kWh, assuming that the heat demand was reduced under the minor retrofitting scenario, can decrease heat energy consumption and CO2 emissions to 35%. As upfront costs of the energy efficiency measures are high, a carbon offset mechanism could facilitate the implementation of university building modernization.

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