Seeking help with the dew point issue of purified air

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The company currently operates two sets of centrifugal compressors and two sets of waste heat drying and regeneration systems. The online dew point measurement for the waste heat drying and regeneration systems indicates around -70°C, while the temperature at the outlet of the purified air is around 40°C. The equipment is located inside the factory building; however, there is another online dew point detector along the path of the purified air from the factory building to the storage tank for this air, showing a value of around -27°C. At present, the winter temperature is -9°C, and the required temperature for the purified air according to the process specifications is -40°C. The distance between the factory building and the purified air storage tank is about 60 meters. I also asked the equipment manufacturer why there was such a large difference between the dew point at the equipment’s outlet and that at the storage tank. The manufacturer replied that this was normal, as there is a difference due to high pressure and low temperature, especially given the large temperature difference between the factory building and the outside environment. (Manufacturer’s response: Due to winter conditions, low temperatures and high pressures facilitate the accumulation of moisture. The dew point is -40°C, with 0.172 g/m3 of moisture in each cubic meter of air. If a dryer has a capacity of 100 m3/min, then 17.2 grams of water are present in the air per minute, 1032 grams per hour, and 24,768 grams in 24 hours. The dew point tends to get worse over time.) I would like to ask experts: what are the reasons for such large variations in the dew point?