Techno Economic Evaluation and Feasibility Analysis of a Hybrid Net Zero Energy Building in Pakistan: A Case Study of Hospital

 The current study is an economic evaluation and feasibility study of hybrid microgrid Net Zero Energy Buildings in Pakistan. A Net Zero Energy approach is proposed for a two-story hospital building situated in Taxila, Pakistan. Consequently, to design a hybrid Net Zero Energy Building, the solar radiation potential of the subject location and electricity usage of the hospital are estimated. The proposed hybrid microgrid Net Zero Energy Building comprises photovoltaic modules and converters. However, the thermal load is computed as a grid-connected hybrid system. Economic evaluation is performed by using economic indicators of the net present cost and the payback period. Also, initial and operational costs are determined, to determine the profitability of the project. Results show that the analysis is a cost-effective approach and has a payback period of 2.53y. Additionally, the per-unit cost of electricity is reduced to 0.12 USD/kWh. Moreover, the energy produced by a hybrid system is 10.24% more economical than that of the pre-working grid system. Results explain the reduction in the cost of energy and profit margin in electricity generation and the increase in electricity production and feasibility of hybrid Net Zero Energy Buildings in Pakistan.

Introduction

In the past few decades, energy consumption in buildings has been increased to 30% worldwide. Renewable energy is not a new concept to work with. Many researchers are already working on various renewable energy systems to reduce capital costs and increase energy production. In a study, the water management of PEM fuel is inspected, and, according to the results, the effectiveness of PEM fuel cells is at maximum at 80°C with the removal of wastewater periodically . In another research, the importance of simulation and optimization techniques is highlighted by working on PEM fuel cells in the energy sector. Results conclude that by the simulation of operating pressures and voltage parameters as working parameters, the energy and exergy efficiencies are 47.6 and 50.4%, respectively. In a study of the PEM electrolyzer, the payback period for the hydrogen generation systems is observed. 

Methodology

In this particular research, a hybrid microgrid NZEB is proposed for the hospital building situated in Taxila, Pakistan. The aim of the current research is to minimize the electricity consumption expenditure of the hospital by implementing RE techniques as well as to check the feasibility of NZEBs for the Pakistani climate. So, the total thermal load is calculated for a hospital located in Taxila, Pakistan, using ASHRAE thermal load equations. Also, an energy-efficient model is developed in HOMER Pro software by using variables of NPC, operating cost, and payback period. Later on, sensitivity analysis and optimization of the parameters are performed.

Building Design

To design the building, the most important task was the selection of a site in order to perform a feasibility analysis of NZEBs in Pakistan.

Site Selection

On the basis of climate condition, Pakistan is divided into five zones. However, the highest temperatures range, i.e., 25–127°F exists in zone D. Therefore, in this study, a hospital building is selected for the conversion into NZEB in zone D in Taxila, and it has a latitude of 33.43°N and longitude 72.8397°E. the solar potential of Pakistan for different cities is highlighted. It can be clearly seen that the selected zone has a high potential for energy production and development of NZEBs in Pakistan

Zone Identification and 3D Modeling

After selection of building type and site, a 3D model is designed in Heat Cad software. In the current research, the hospital building is comprised of five offices, a patient ward, ICU, radiology, two laboratories, operation theater, pharmacy, and washrooms. However, identification of zones is dependent on the type of work, thermal conditions, and human comfort.

Thermal Load Assessment

The current hybrid on-grid system is designed to meet the electricity needs of a hospital building in Pakistan using solar energy as an alternative energy resource in addition to a conventional grid. The estimation of the thermal load is carried out carefully, taking into consideration the load requirements of the hospital building for the peak summer season.

Homer Program

HOMER is one of the best tools for designing renewable-energy-based systems. Moreover, it can simulate the operations of a hybrid system for an entire year in time steps from 1 min to 1 h. It also enables us to compare and evaluate the disadvantages and advantages of economic and technical features. In HOMER, the design process is performed in three steps: simulation, optimization, and sensitivity analysis. In this paper, all three processes are followed to get the best overview of the feasibility of NZEBs in Pakistan.

Conclusion

The current study is an economic evaluation and feasibility analysis of hybrid microgrid NZEB. A hybrid PV power system is created to supply energy to the hospital building located in Taxila, Pakistan. The objectives were to decrease the total electricity price and feasibility analysis of hybrid NZEBs in Pakistan for non-residential buildings. To attain maximum advantage from the proposed hybrid NZEB system, the designing of the building, calculation of thermal load, simulation, and optimization of the suggested hybrid microgrid NZEB were all performed in HOMER Pro. An optimal range of design parameters was acquired using thermal data and solar irradiance as input. Additionally, an economic analysis was performed to evaluate the feasibility of the proposed hybrid system over the duration of 25y