Double glass wall protects butterflies
The Milwaukee Public Museum has gone to great lengths to protect its vast collection of butterflies from the harsh Wisconsin climate. Part of a 14,500-sq.-ft., $6.5 million addition to the museum, the new Puelicher Butterfly Wing features a "double envelope" curtain-wall system to help maintain a tropical environment needed to permanently house butterflies year round. Designed by Minneapolis-based A/E Hammel Green & Abrahamson Inc. (HGA), the system is composed of two glass walls spaced 3 feet apart, creating an insulation barrier that maintains a constant 80 F inside air temperature with 85 percent relative humidity. The structure utilizes light shelves to protect the space from overheating in the summer months, while passive solar heat helps warm the interior in the winter.