A series of four solar energy workshops will be held on the Loudeun campus of Northern Virginia Community College, beginning today at 9:30 a.m. Dr. Maurice Raiford will present a historical and scientific everview of the development of varied forms of solar energy. The cost per session is $10 a person as $15 a couple. Other day-long seminars will be held July 30, Aug. 13 and Sept 17. For information, call 323-4551.

The Red Carpet national real estate office franchising operation has added the following area offices: Beltway Homes, Inc., Lanham; County Wide Realty, Gaithersburg Regent Realtors, Rockville, Stan Ridgeway Real Estate, Silver Hill, Alexandria and D.C.; Al Smith Realty, Alexandria and McLean, and Thompson Co., Silver Spring.

The Department of Housing and Urban Development has awarded a $13,475 grant to contractor Sterling Nichols to build a solar-powered house at Kingsmill on the James, a 2,500-acre residential-resort community being developed by Buseh Properties, Inc., near Williamsburg, Va.

Pittarelli Realty, an affiliate in the Realty World franchise, has opened a branch office in Clifton, Va.

The written examinations for brokers and sales agents in the District will be given at 8:30 a.m. July 26, at the Quality Inn at 415 New Jersey Ave. NW at 8:30 a.m.

KRB Inc., a real estate development firm based in Seabrook, Md, plans to build 170 single houses on 165 acres in the Greenbelt-Seabrook area of Prince George's County. Foundation work on the first 27 houses, to be priced from $78,000, will begin next month at the Forest at Woodstream, according to Michael Rose, KRB president. Models will be opened late this year.

A new section of four and five-bedroom homes, priced from $134,300, has been opened at Potomac Chase Estates by Rocky Gorge Develoopment Corp. Sites in the Potomac development are two or more acres. The site is on Query Mill Road, just beyond the Potomac Polo Club.

Brannock Associates, working with Barnes, Morris & Pardoe, has arranged a lease for approximately 9,000 square feet of office space at 1627 K St. NW. a new building nearing completion by the John Akridge Co. The lease is with Gannett Co., Inc., a national newspaper publishing firm.