Georgetown University has received a $1 million pledge from an alumnus in Hong Kong toward construction of a $27 million intercultural center whose roof will be covered by solar electric generating units.

The Rev. Timothy S. Healy, S. J., president of the university, yesterday announced the gift from Eric Hotung, an international real estate developer and businessman who graduated in 1951 from Georgetown's School of Business Administration.

When the intercultural center is completed in 1982, it will be the world's largest solar-powered building, Georgetown officials say. The six-floor, 175,000-square-foot center will contain classrooms, study areas, offices, a communications center and a 400-seat auditorium.

Its 600-foot-long roof will be covered by photovoltaic cells -- silicon wafers that turn the sun's rays into electrical energy that will be fed into the university's electrical system. The Department of Energy also is providing some financial support for construction of the building as a major demonstration of solar energy's potential.

It is a key part of a long-range plan to make Georgetown University self-sufficient in energy. Included in the program are a $7.4 million sports center constructed below ground level to minimize air conditioning and heating requirements, and a $14 million steam heating and cooling plant employing the latest technology in burning coal without smokestacks or air pollution through a new process called fluidized bed combustion.

The intercultural center will contain the School of Foreign Service, School of Languages and Linguistics, and the departments of Latin American Studies, Russian Area Studies, Middle East Studies, Business Diplomacy, German Public and International Affairs, and American Studies, Georgetown intends the center to provide a focal point for its efforts to improve international communications and understanding a spokesman said.

At Hotung's request, a memorial plague to Dr. Sun Yat-Sen, often described as the father of modern China, will be placed in the center's main hall. Hotung is the grandson of Dr. Robert Hotung, who was a friend and contemporary of Sun Yat-Sen, a university spokesman said.

"We are honored that the father of modern China is commemorated in an intercultural center where people of all faiths and ideologies will come to study," Healy said. "Thanks to Eric Hotung's generosity, students from China and allover the world will come to Georgetown to study in a magnificent new building and to learn of each other's perceptions, histories, languages and outlooks." Healy will conduct a cornerstone blessing ceremony today at 4 p.m., university officials said.

Technical information from the solar photovoltaic roof installation will be provided to the British Crown Colony government in Hong Kong under an exchange arrangement requested by Hotung.

Hotung became a member of Georgetown's board of directors last year. He is considered a pioneer in construction of low-cost housing in Hong Kong, offering units for sale in the 1960s with mortgage installment payments lower than existing rental costs. He established a trust fund in 1965 to help underprivileged Chinese students receive higher education, professional training and vocational education overseas.