It might seem to be an oversized, mechanical version of the children's game Chutes and Ladders. But the 32 holes to be dug and two miles of pipes to be laid next week on an 11-acre building site at UC Davis will test installation methods for a pilot project that will circulate water below ground to heat and cool a new residence complex for 650 students. Another 720 holes will be dug and 36 miles of pipes will be laid next spring to install the heating and cooling infrastructure before construction begins on the 27-building complex. The underground tubing arrays to be used in the project modify existing technology to reduce costs, says Dick Bourne of the Davis Energy Group. The system was developed in a project funded by Pacific Gas & Electric, the California Energy Commission and the Geothermal Heat Pump Consortium. With piping placed in backfilled holes 20 feet in depth and three feet in diameter, the system will circulate water down a vertical tube and pump it back up a helical tube to draw warmth or coolness, depending on the season, from the surrounding earth before the water is fed through a heat pump system. The ground loops also will be used to heat water for two laundry facilities. Bourne estimates the system will result in annual energy savings of $30,000, or more than 30 percent, compared to the cost of operating a conventional heating and cooling system. John Yates, who represented the university in negotiations with private developers Tandem Properties and the Hamel family of Davis, says student residents will benefit through lower heating and cooling costs for their units. Pyramid Construction of Davis will build the complex of studios to four-bedroom apartments, scheduled to open in the fall of 2000.