Initial Thesis Project Summary Report



CHAD ALLISON MECHANICAL BALTIMORE, MD

Proposal

December 5, 2002

Building Background

The Walter's 1974 building is 86,000 square feet and contains multiple gallery spaces. The spaces are conditioned by a variable air volume system which keeps the galleries at 72oF and 50 % relative humidity. The air is supplied by 8 air handling units ranging in size from 1,000 cfm to 52,000 cfm. Chilled water is supplied to these air handlers via three electric centrifugal chillers, with most of the cooling being handled by the 350 ton unit. The remaining two are cycled on as needed during peak cooling periods. As for heating the hot water is supplied by converting steam from one of the three boilers to hot water. The steam from the boilers is also sent through a steam to steam heat exchanger to be used for humidification in the air handling units. There is nothing unusual about the existing systems in the building.

Problem

Buildings are the one of the largest energy users in the world, and Walters Art Gallery is no exception to this statement. The 1974 building is a major energy user, due to the large loads and need for conditioned space twenty four hours a day, seven days a week. My goal for thesis is to redesign the mechanical systems in my building to be more efficient. This in turn will reduce the energy consumed and inherently reduce the operating costs.

Description of Alternatives

I have thought of two main ways to increase the efficiency of the buildings mechanical systems. The most prevalent one in my mind is fuel cell technology. I believe that I can create a electrochemical system which will produce a major part of the electricity for the building while also generating the steam for heating and cooling. With a system such as this the owner could reduce his overall electric use from the electric company and use the by product (steam) increasing the overall efficiency of the system.

The second idea was to use a dedicated outdoor air system in addition to a radiant cooling system. Although this system would definitely save on energy it had many drawbacks due to the uses of the building. The main snag would be the water flowing above valuable pieces of art work. The second restriction is the possibility of condensation, all though if the system is designed right there is a minimal chance. These two things would never be allowed by the owner. They will not let water run anywhere near the displays.

Proposed Redesign

My proposed redesign of the building mechanical systems is the first alternative mentioned above. I would like to use solid oxide fuel cell technology to generate electricity and steam for the building. By doing this I hope to reduce the overall operating cost of the system.

The fuel cell would use natural gas for power generation, therefore eliminating or at least minimizing the service from the electrical company. One of the benefits of using a solid oxide fuel cell is their high operating temperature (700oC-800oC). With these temperatures it would be possible to use the fuel cells as “boilers” to generate the steam needed to heat the building. The steam generated could also be incorporated to cool the building with the implementation of absorption chillers.

With the use of this system there would be the need to remove the existing electrical centrifugal chillers and the existing natural gas boilers. The cooling tower, which is contained on the roof, will have to be resized due to the drop in performance of the absorption chillers when compared to the centrifugal chillers. Also there would be the need for an inverter to go from direct current to alternating current and the introduction of a new transformer to achieve the voltages needed by the building.

I will be looking into using a turbine to reduce the high pressure steam, which will be generated by using waste heat from the fuel cell, to low pressure steam. The benefits of this would be the additional production of electricity while reducing the steam to the pressure needed for the mechanical systems. There will be the need of some energy storage due to the transient loads associated with the building during typical operation. I will look into the possible use of batteries or heat storage for this purpose.

There are many ways in which a system such as the one I am proposing may be implemented. A schematic of the system that I believe is the best and am most informed about as of now, is located in the appendix. However I may find, through research, a system that would be better from an operation standpoint for my building. The schematic is just a guideline on how the system will work based on information I now know.

Justification

I want to create this system because it is something of interest to me, plus it would be extremely educational. As far as I know there has never been a thesis which has incorporated this technology. This project is something off the beaten path, which I can learn from and and possibly provide the department with valuable information concerning the use of fuel cells in buildings.

Not only is the educational value of interest but the efficiency of the proposed system is also important. I would like to research the possible energy savings of my proposed system. Fuel cells are efficient electrical energy producers, but the other implications due to the co-generation system should also have some inherent benefits.

I do realize that there will be downfalls with such a system, the main of which is going to be first cost. There is interest in finding out just how long it would take to payback when compared to the typical system, which is now in place. There is also questions of maintainability of fuel cells due to there relative newness. Unfortunately I am unsure if there will knowledge available to answer question pertaining to this problem due to the lack of information on such systems.

Tools, Methods, and Limitations

The electric bill from the existing design will give me the basis for my electric load. Then using the information of equipment being replaced, the new electric load can be found. Once this is found calculations can be performed for sizing the fuel cell and the excess heat produced. These calculations will be performed by hand and come from research and knowledge from the class I took on fuel cells. Trane Trace may also be used if a model can be built that closely represents most of the system, mainly the chilled water and hot water systems.

The limitations will be more of time limitations. There is a lot that needs to be done with a system such as the proposed one. Everything could be accomplished if problems do not arise that takes a week or two to solve, which will probably happen. The other limitation may be data from manufacturers. There are only a limited number of manufacturers who could answer product oriented questions. Siemens Westinghouse will hopefully be a good source of information. I am currently trying to make contact with someone in their Solid Oxide production facility.

Integration and Coordination

I am going into depth for the redesign of the mechanical and electrical systems, since fuel cells are so closely related to both options. I will have to find the electrical load for my building and base the size, and operation of my fuel cell based on these numbers. Then once the size of the fuel cell is determined calculations will be done to find the steam generation from the fuel cell for my mechanical redesign.

Other considerations that will be taken into account are the cost implications of fuel cells. I shall look at the first cost and payback period if possible. The problem with this task is finding prices for components of such a system. If trouble arises with this task I will calculate the savings due to energy and use that as the factor to justify how much could be spent on the fuel cell system initially. This should complete the breadth requirement for construction management.

Structural issues may arise during research, which will make me look into structural implications. This could happen when the overall size and weights of the fuel cells are found. Space will be available in the existing basement mechanical rooms, which should keep me from adding on to the structure. I believe that there may be the need to increase the size of the cooling tower. If this happens I will make sure to look at how it is supported currently and if the additional loading will have an affect on the supporting members.

Overall I believe that my thesis will involve the integration of all options in some manner. Since this is one of the first theses to attempt fuel cell integration I am unsure of all the implications. I can only confront the problems as more is learned of the system and my possible design. Through this project I hope to learn of problems a system such as the one proposed can create in a building design and construction and hopefully address them.

Conclusion

Fuel cells are a new technology which can be applied to the building industry. Through my thesis research I hope to show that a system such as the one proposed can work and is feasible. I have taken a fuel cells class which has taught me the workings of a fuel cell and the intrinsic problems with such new technology. Due to my firm background in the building industry and my willingness to learn of fuel cells I believe I can complete this thesis and make it informative.

Integration and Coordination

I am going into depth for the redesign of the mechanical and electrical systems, since fuel cells are so closely related to both options. I will have to find the electrical load for my building and base the size, and operation of my fuel cell based on these numbers. Then once the size of the fuel cell is determined calculations will be done to find the steam generation from the fuel cell for my mechanical redesign.

Other considerations that will be taken into account are the cost implications of fuel cells. I shall look at the first cost and payback period if possible. The problem with this task is finding prices for components of such a system. If trouble arises with this task I will calculate the savings due to energy and use that as the factor to justify how much could be spent on the fuel cell system initially. This should complete the breadth requirement for construction management.

Structural issues may arise during research, which will make me look into structural implications. This could happen when the overall size and weights of the fuel cells are found. Space will be available in the existing basement mechanical rooms, which should keep me from adding on to the structure. I believe that there may be the need to increase the size of the cooling tower. If this happens I will make sure to look at how it is supported currently and if the additional loading will have an affect on the supporting members.

Overall I believe that my thesis will involve the integration of all options in some manner. Since this is one of the first theses to attempt fuel cell integration I am unsure of all the implications. I can only confront the problems as more is learned of the system and my possible design. Through this project I hope to learn of problems a system such as the one proposed can create in a building design and construction and hopefully address them.

Work Plan

Christmas Break

• Research done

1/13/03 - 1/24/03

• Find definite size of electric load

• Size absorption chillers

• Find amount of steam needed

1/25/03 - 2/14/03

• Size Fuel Cell

• Size steam to hot water converter

• Find amount of excess heat production from fuel cell

• Find good balance between heat and electrical load

• Size heat exchanger

2/15/03 - 2/28/03

• Size turbine and electrical load produced

• Size DC/AC inverter

• Size transformers

3/1/03 - 3/7/03

• Find dimensions of fuel cell and weight

• Find dimensions of absorption chillers

• Place new equipment in designated areas

3/8/03 - 3/28/03

• Find cost of new system

• Compare cost of old and new to see savings

• Justify amount of money which could be put toward fuel cell system based on savings

3/29/03 - Presentation

• Finish up all loose ends

• Complete thesis

• Create presentation

References:

Mench, Matthew. Assistant Professor of Mechanical Engineering, Associate Director, Electrochemical

Engine Center.

(Dr. Mench was the Professor for the fuel cell class which I took. Fuel Cells are his area of expertise and I fill confident about his knowledge of the subject.)

Siemens Westinghouse. No contact person yet.

(The site contains information on their fuel cell production along with technical data. Also contains. Site also contains information pertaining to their research and applications)

Ellis, Michael W. Fuel Cells for Building Applications. American Society of Heating, Refrigerating, and Air Conditioning Engineers Inc. Atlanta GA, 2002

(This book goes into general information about fuel cells and their application to buildings. It

also contains quite a bit of information on co-generation systems which is extremely useful)

Larminie, James, Dicks, Andrew. Fuel Cell Systems Explained. New York: John Wiley & Sons, 1999

(This book goes into the exact workings of a fuel cell. It describes the parts involved and the calculations needed to size fuel cells.)

Ballard Power Systems.

(Ballard is a world leader in Fuel cell technologies especially PEM fuel cells. They have actually

working stationary systems that are now being field tested.)

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