James Frye drove his air conditioned taxi through the streets of Washington yesterday, happily calculating that he'd earn a profit of about $65 in six hours -- about one-third more than one most summer days.

"All the cab drivers with no air conditioning went home," chuckled Frye. "I get their business, plus the fares of all these people who don't want to walk in the heat."

For Frye and dozens of other businessmen in the Washington area there has been profit in the past two days of adversity. While most of us swelter and curse the 100-degree heat and high humidity, they have happily gone about their businesses to the clink of the cash register as well as the whir of the air conditioner.

Air conditioners, pool supplies and ice cream tend to be seasonal items, whose purveyors look to the summer heat for much of their livelihood. For cab drivers and hardware stores, summer tends to be a slow period, and heat spells like the current one help them through a slack time.

At Pool and Patio in Rockville, sales have increased by about 20 percent during the past several hot days, according to salesman Todd Offenbacher. Many of the store's customers are buying highly concentrated chlorine for their pools.

"What's happening is everyone's pool is turning green because of the hot temperatures," said Offenbacher. "The heat burns the chlorine out of the water so not much is left to fight the algae."

Other Pool and Patio customers rush in to purchase new pumps, filters, games and floats for their pools. "During hot days, people want to spend more time by the pool and they realize they need more things," Offenbacher said.

At the ice Machine Service Co. in Northwest Washington, president Ted Beverly figures he sold 1,200,000 pounds of ice during the past week to restaurants, hotels, grocery stores and supermarkets.

"Ice sales are very dependent on the weather," says Beverly. "With each degree over 85, sales go up about five percent.

"People want more iced tea and less hot coffee."

Area liquor stores reported that the heat wave has boosted their sales of beer and soda by about 30 percent.

"A lot of guys seem to be quitting work early and stopping in for a cold six pack before they go home and face the heat again," said Frank Bedard, a clerk at Crown Liquors in Green Meadows. "And once these guys come in they're spending a lot more time in the store than they usually do," Bedard said.

The store is air-conditioned.

At the Radishes and Rainbows cafeteria at Connecticut Avenue and L streets NW, owner Harvey Rosenthal stood behind the cash register, happily adding up the cost of the salads, yogurt and sodas that customers bring past him on trays.

Rosenthal figures that the heat wave has helped bring him at least 10 percent more business than last week, and about 40 percent more business than in January.

"People don't want to sit outside on a day like this," says Rosenthal. "They come in here because of the air conditioning and the salads."

A few blocks aways, at 17th Street and New York Avenue NW, tourists lined up by a white truck to buy hot dogs, sodas and ice cream from William Fleming, 16.

Fleming has sold about $300 worth of food during the last two days -- about 10 percent more than during last week, when the weather was cooler.

While some people tried to keep cool by drinking soda and eating ice cream, others relied on more elaborate devices. In the appliance department of Hechts in Prince George's Plaza yesterday, customers were lining up to buy fans and air conditioners.

"Today we'll sell maybe 15 fans, and three or four air conditioners," said salesman Ernest Hipp. "A month ago, if we had sold five fans we would have been doing good."

More fans and more air conditioners is good news for the power companies as well.

"The largest demand for electricity is during the summer," said one spokesman for Potomac Electric and Power Co. During August 1979, for example, the average bill for a one family home was $47.85, while during February 1980 the average bill was only $36.92.

Anyplace where cool air comes for free has inevitably been more crowded than usual.

At the Fair Lanes bowling alley in Hyattsville yesterday, some persons were not as interested in rolling a strike as in taking advantage of the air conditioning.

"Half of these people told me when they walked in, 'we came here because we knew it would be cold, cold, cold," said manager Myra Pyles. "Some people came in and didn't even bowl. They just stood there cooling off."