Actividad clonogénica del compartimento de células cKit+

The second part of the analysis involved the assessment of installing a CHP system both in terms of the resultant impact on energy consumption as well as on economic terms. The analysis was performed by considering the grocery store as part of a residential community in terms of sharing of energy across the grocery store building boundary. As in the first part, the second part was also divided into two steps. The first step dealt with the assessment of the CHP system in terms of the impact on energy consumption. In the second step, an economic

assessment of the CHP system was conducted.

In the first step of the second part of the analysis, an appropriate CHP system was installed to service the electricity and thermal requirements of the grocery store. Surplus energy generated was then matched with the electricity and thermal requirements of the neighboring residential community. To carry out the analysis for this section two models - a CHP model and a multi-family residential model were created in addition to the grocery store model.

The CHP model was used to assess an appropriate CHP system that would serve the needs and requirements of the grocery store. The CHP model provided options for selecting an appropriate prime mover and its mode of operation, thermal cooling technologies and heat recovery strategies. The CHP model was created using Microsoft Excel for Windows (MS-Excel 2010). The multi-family residential model was adopted from the simulation model⁴ created for the IC3 code compliance calculator developed by the Energy Systems Laboratory (Kim 2006, Malhotra 2009). The model was constructed using specifications prescribed in the International Energy Conservation Code (IECC 2009) for Texas Climate Zone 2. In addition to the above mentioned models, the grocery store simulation model created in eQUEST Refrigeration was modified to better accommodate the operation of the CHP system. Modifications include provisions for hot water boilers, absorption chiller model for space cooling as well as medium and low temperature absorption refrigeration and a sub-cooler model.

4 An input file created using DOE-2.1e (Wikelmann et al. 1993) whole building energy simulation software program is used to run the IC3 calculator. This study used this DOE-2 input file to conduct the analysis.

94 Figure 4-3: Research Methodology – Part II

MULTI-FAMILY MODEL

Is % savings of whole building energy consumption at source

above original base-case

> = 20%?

NO

4 OPTIONS FOR HIGH PERFORMANCE STORE w/ COGENERATION

YES

ECONOMICS MODEL

STEP 1: ENERGY CONSUMPTION CALCULATION MODEL

LOADS FROM

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In the CHP model, several options for a grocery store were selected, which presented a reasonable amount of both electricity and thermal energy consumption. The options were selected to present varying degrees of usage of waste thermal energy generated by the CHP system installed in the grocery store. The building loads obtained from the selected option were matched with the electric power and waste thermal energy generated by a prime mover selected in the CHP model. The surplus loads were then matched to the loads from the multi-family model and the resultant number of dwelling units being served by the surplus energy was determined. The output was assessed in terms of annual, monthly and hourly energy

consumption. The output was also evaluated in terms of site and source energy consumption. A site to source energy factor of 3.15 was used for electricity and 1.1 for natural gas. These factors are obtained from the Annual Energy Review published annually by the U.S. Energy

Information Administration (EIA 2010). The site to source conversion for electricity also accounts for 7% transmission losses. The objective of the analysis was to determine the highest percentage reduction above the base-case model, which included the energy consumption of the unmodified grocery store with implemented energy efficiency measures and the multi-family units that could potentially be served by the surplus energy from the CHP system implemented in the grocery store. An arbitrary cutoff percentage of 20% above base-case was selected.

Finally, four options satisfying the criteria for reduction in energy consumption were selected to proceed to the second step. Details of this step are provided in Chapter 7 of this study.

In the second step, an economic assessment was performed. The analysis implements two typically used methods for the assessment - life-cycle cost analysis and payback period analysis. Several metrics that are commonly used for economic assessment were used to conduct this analysis. The measures include assessing the simple payback period and investor’s rate of return (IROR) when performing the payback period analysis; and assessing the net present value (NPV), time until net present value and internal rate of return (IRR) of the project when

performing the life-cycle cost analysis. Details of this step are provided in Chapter 8 of this study. A flowchart diagram for Part II of the analysis is presented in Figure 4-3.

4.4 Summary

This chapter provides an outline of the methodology used in this study. The

methodology used in this study was developed to assess the reduction of energy consumption in grocery stores in a hot and humid climate. Hence, a single location representing the hot and humid climate was selected for the analysis. The assessment is then divided into two parts. In

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the first part, the energy reduction of the grocery store was assessed on a building level. In this part a calibrated base-case building was modeled. Several energy efficiency measures were evaluated using this model. The energy reduction was monitored at both site and source levels.

In the second part, reducing energy consumption in the grocery store was addressed by considering appropriate CHP systems. Surplus energy was then shared across the boundary of the store with the surrounding residential community, which in this case, were multiples of an 8-unit multifamily building. Here too, the energy reduction was monitored at both site and source levels. An appropriate economic analysis was subsequently performed. Finally, the energy consumption of the base-case grocery store building, and results from the two parts were compared side-by-side and the total reduction in energy consumption at site and source levels was determined.

97 CHAPTER V