The tunnel temperature stabilization system of the McMath-Pierce telescope will be upgraded to reduce energy costs associated with operation of the solar facilities on Kitt Peak. The above-ground portion of the telescope cooling system consists of a pump that circulates a 38% solution of glycol through the telescope skin panels, some interior panels near the top, and cooling coils embedded in the concrete deck on the telescope's top, before returning to a 16,000-gallon storage tank. The glycol in the storage tank slowly absorbs the heat from the telescope as the solution is circulated, keeping the upper telescope at a temperature approximating the prevailing outdoor air temperature. At night, the absorbed heat is re-radiated away to the night sky by the circulating liquid.
The motor currently driving the pump is 25 hp. It is estimated that a cost savings of 5-10% could be realized by replacing the existing motor with a high-efficiency motor along with a variable frequency drive (VFD) unit. Studies indicate that the flow could be reduced at night without affecting telescope performance. The VFD unit will allow this to be tested. Any reduction in the flow at night would translate to further savings on energy cost.
The 25 hp high-efficiency motor and VFD have been ordered and installation is planned for the spring quarter.
Claude Plymate, Dan Little,
Randy Feriend, Teresa Bippert-Plymate