Some scientists believe that the sun grew larger during the Maunder Minimum (Little Ice age of 1645) and a bigger sun gave off less heat. The correct observation is that during the Maunder Minimum the sun did grow slightly in size but gave off less radio wave energy.
If you look at my solar chug theory you will learn that every ~2,000 years the planets align within a tight number of degrees. This imparts a gravitational shear to the sun which makes it rotate faster. When it rotates faster centrifugal force makes the outer layers of the sun move away from the inner core. Since we know that sunspots and solar radio waves are produced by the inner core bumping into the outer layer this bumping becomes less frequent when the space between the inner core and outer layer is greater. An increase in rotational speed of 3-4% is all it needs for this to happen.
Keep in mind that centrifugal force will make celestial bodies swell at their equator. Just as the earth is oblate at the equator (though its true shape is not usually depicted) all celestial bodies that rotate are oblate, the sun is no exception.
The faster the sun rotates the more it swells or oblates at its equator.
Since the majority of sunspots are produced along a narrow band along the equator of the sun, when the sun spins faster the core and outer layers are separated more from the inner core by the expanding equatorial oblateness, and the sun appears to swell and and less sunspots are produced.
Over years the suns rotation slows once again and the inner core and outer layers come closer together, they bump more frequently, and more solar radio waves are produced in the butterfly pattern along its equator and a warming period begins.
This all fits possibly with my solar chug theory and periodic warming of the planets in our solar system due to saltwater absorbing radio wave energy.
The suns rotational speed is affected by periodic gravitational shear by planetary alignment imparting rotational energy to the sun.