Requires the best possible heat absorber with lots of surface area if possible or an Anodized plate to accept and absorb maximum heat flow before it passes and goes into the environment. You will always have heat dissipating to atmosphere, the trick is to limit that loss as much as possible. A dense heat sink with lots of fins densely (anodized) is the best but not always possible. In a heat sink case heat is absorbed and concentrated close to the module array limiting heat flux travel to the modules hot side surfaces, the shorter the path the better. If the heat path is to long than the thermal resistance of the material will limit the ability for it to reach its target and dissipate to environment before it can be fully adsorbed.