I'll always remember buying my first furniture as an adult. The owner of the furniture store came up to me after I completed the purchase. I told him that his prices were better than I expected. He responded, "I want to get rich, but get rich slowly."

That's actually the surest and easiest way to accumulate wealth -- do it over a long period of time. But is there another way for those who don't want to wait so long? I think so. These three dividend stocks can double your money in under seven years.

1. Brookfield Renewable

Brookfield Renewable (BEP -1.66%) (BEPC -0.89%) owns and operates hydroelectric, wind, solar, and distributed energy facilities. Its operations span four continents and combined generate 24 gigawatts of power.

The stock has delivered an average total return of 16% annually over the last two decades. Brookfield Renewable's distributions played an important part in that stellar performance and have risen by a compound annual growth rate of around 6%.

How can Brookfield Renewable potentially double your money in under seven years? The company expects to continue delivering average annual total returns of between 12% and 15%. Even at the low end of that range, an initial investment would double in a little over six years.

Brookfield Renewable should be able to achieve this growth thanks to an unstoppable trend -- the ongoing shift from fossil fuels to renewable energy sources. Countries across the world have established aggressive goals to reduce carbon emissions significantly by 2030. Brookfield Renewable's facilities offer more cost-effective ways to generate electricity than either coal or gas.

2. Digital Realty Trust

Digital Realty Trust (DLR 0.63%) is a real estate investment trust (REIT) that owns more than 300 data centers. It has over 4,000 customers, including many of the world's largest technology companies. 

REITs must return at least 90% of their taxable income to shareholders in the form of dividends. Digital Realty Trust has an impressive track record on this front, having increased its dividend for 17 consecutive years. Its dividend yield currently tops 4.8%.

Digital Realty Trust should benefit from multiple growth drivers over the next several years. Organizations continue to move their apps and data to the cloud. The application of artificial intelligence seems to be near a major inflection point. The adoption of 5G networks and the corresponding explosion with the Internet of Things should also boost demand for data centers. 

Global consulting firm McKinsey & Company projects that digital infrastructure demand will increase by a compound annual growth rate of 10% to 13% through 2026. With its strong dividend included, Digital Realty Trust doesn't have to grow at even the low end of this range for its total return to at least double investors' money over the next seven years.

3. Medical Properties Trust

Medical Properties Trust (MPW -0.22%) is another REIT stock that could be a big winner. The company leases 435 facilities with around 44,000 licensed beds to hospital operators in 10 countries.

The hospital REIT's dividend yield of 9.4% is especially attractive. Medical Properties Trust has increased its dividend for eight consecutive years, a period in which several of its peers cut their dividend payouts. 

This stock could nearly double simply by regaining its level from early 2022. Some of Medical Properties Trust's tenants faced financial challenges, which in turn caused investors to be uncertain about the REIT's prospects.

However, the outlook is improving for hospital operators with increased reimbursement from Medicare and private payers. That should ultimately lead to a restoration of investors' confidence in Medical Properties Trust. And if the REIT can at least maintain its dividend at current levels, its share price won't have to rise very much to give investors a total return of 100% or more in under seven years.

An important caveat

The opportunities for each of these three dividend stocks to double your money in less than seven years are real. However, there are always challenges that could prevent these gains from materializing. The most reliable way to make a lot of money with stocks still mirrors what that furniture store owner said to me years ago: Get rich slowly.