This equipment is a km2 level throttling liquid nitrogen refrigeration loop model equipment with pressure, which is mainly used to undertake the thermal vacuum and thermal balance tests of various aerospace products. The equipment has the advantages of fast temperature rise and fall rate, convenient operation, high reliability, and long-term stable operation. One set of liquid nitrogen system can be used for two sets of loop model equipment at the same time, and the liquid nitrogen recovery rate is more than 85%, which greatly saves the manufacturing cost and operation cost. Suitable for large and medium ring die equipment.