As a result of constantly increasing data center utilization, many challenges have appeared for thermal engineers over the last few decades. Advanced cooling systems for servers are of significant interest, particularly, technologies which can also reduce electricity usage. One known technology called Organic Rankine Cycle (ORC) is considered a viable alternative for this purpose. It can both the heat from a server and then transfer the server heat into a power cycle to generate electricity.
This study consists of the design and construction of an experimental prototype of 20kW of waste heat, representing two common rack servers operating at full capacity. The range of server waste heat temperatures is between 60°C to 85°C, which is far below the normal operating range for ORCs. This ultra-low-grade waste heat leads to an expected thermal efficiency between 2%-8%. Tests on the experimental rig showed a maximum thermal efficiency of 3.33%. The system is both absorbing all the waste heat from the data center and at the same time providing an economic benefit back to the data center in form of electricity. Through experimental investigation, this study provides the first evidence for using ORC system as a valid solution for ultra-low-grade waste heat recovery.
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Integration of a Solid Oxide Fuel Cell with an Organic Rankine Cycle and Absorption Chiller for Dynamic Generation of Power and Cooling for a Residential Application
The high temperature exhaust heat from a solid oxide fuel cell (SOFC) can be captured and used as the primary thermal energy source for bottoming cycles. In this study, the waste heat from a fuel cell is captured and processed either through an organic Rankin cycle (ORC) to provide extra power or an absorption chiller (AC) to provide cooling for meeting the dynamic cooling demands of a residence/community. A spatially resolved dynamic model was developed in Simulink to study dynamic characteristics of an SOFC system. Also, a dynamic model was developed for the ORC and AC to study the dynamic characteristics and performance of the integrated system. This model was then used to evaluate the efficiency, capacity, and dispatchability of the system, based upon meeting measured load profiles of residential buildings. Dynamic data from a residential complex were used as an input to evaluate the dynamic system model. The SOFC was capable of following the highly dynamic load with an average electrical efficiency of 46%. An average of 7% more power was produced through the ORC cycle with an average efficiency of 10%. The AC generated an average 125 kW of cooling with an average coefficient of performance (COP) of 1.08.
more » « less- NSF-PAR ID:
- 10117528
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Fuel Cells
- Volume:
- 19
- Issue:
- 4
- ISSN:
- 1615-6846
- Page Range / eLocation ID:
- p. 361-373
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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