摘要：The fea.ibility of em.loying sta.d-a.one sola. energy system. to m.et dem.nd-side loa.s depends strongly on providing a.propria.e sola. energy stora.e. The present pa.er presents a. efficient a.d econom.ca., underground, therm.l stora.e design to store hot wa.er a. a.tem.era.ure of a.ound 180?C required for running a.double effect a.sorption chiller to cool a.zero-energy-house in a.desert environm.nt. The perform.nce of the design is eva.ua.ed em.loying a.specia.ly developed efficient m.them.tica. m.del, for sim.la.ing the stea.y sta.e ra.ia.ion, convection a.d conduction processes occurring within the stora.e unit. The m.del is presented a.d a.a.yzed, a.d em.loyed to investiga.e the effects of va.ious design pa.a.0}ters on stora.e efficiency. It is dem.nstra.ed tha. high stora.e efficiency m.y be rea.hed, providing tha. a.propria.e insula.ion m.teria.s a.e used. It is a.so revea.ed tha. the soil conductivity ha. little effect on stora.e efficiency.