Geothermal Energy Systems
Scenario: School HVAC Retrofit
A school in Indianapolis, IN is converting their East Wing to a year-round school. During the traditional academic year, the East Wing is use for grades 1-3, but during summer, the rooms will be used for kindergarten prep and other pre-school activities.
The school was originally constructed in the 1950s and only has a central boiler system for heating with no cooling. The classrooms have no ductwork and are heated with unit ventilators and baseboard convectors. Because of the need for heating and cooling in the East Wing, and the lack of an existing central system, the school has elected to install a geothermal heat pump system. Your firm has been hired to prepare the geothermal system design. The existing unit ventilators and baseboard convectors are to be removed under a separate contract.
The school requests a screening of multiple GHX options, and a final design of the most suitable GHX choice:
(a) Complete and submit TWO GHX designs.
Site Conditions.
A) A site plan and classroom drawings can be found on the course website.
B) A 250-ft vertical test borehole was drilled at the site, and an in-situ thermal conductivity test was conducted by another firm. The geologic profile consists of mixed fine to coarse sand to 150 ft, underlain by hard limestone. The thermal conductivity of the geologic materials as determined from the field test is 1.6 Btu/hr-ft-oF.
C) The water table is about 20 ft deep, and there are a number of water wells in the county, some with good flow rates (you’re told hundreds of gallons per minute), but there are rumors that the water is “hard”, and is possibly prone to scaling.
D) There are water-well drillers in the county, about 100 mi. away with experience in both water well drilling and installation of closed-loop (u-pipe) borehole heat exchangers.
E) A few drilllers that have been contacted are concerned about drilling into the hard limestone – it will take more time and incur high costs. However, they are capable of drilling to ~500 ft deep.
Download:- hw1-design-day-loads.xls
Download:- hw1-drawings.pdf