Annual report [Section 13 and 15(d), not S-K Item 405]

Summary of significant accounting policies - Revenue (Details)

v3.25.1
Summary of significant accounting policies - Revenue (Details) - USD ($)
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Disaggregation of Revenue [Line Items]    
Revenue $ 22,619,536 $ 25,139,419
Products    
Disaggregation of Revenue [Line Items]    
Revenue 4,443,996 8,859,946
Products Segment    
Disaggregation of Revenue [Line Items]    
Revenue 4,443,996 8,859,946
Products Segment | Cogeneration    
Disaggregation of Revenue [Line Items]    
Revenue 2,677,930 2,761,667
Products Segment | Chiller    
Disaggregation of Revenue [Line Items]    
Revenue 1,647,374 5,303,978
Products Segment | Engineered Accessories    
Disaggregation of Revenue [Line Items]    
Revenue 118,692 794,301
Services Segment    
Disaggregation of Revenue [Line Items]    
Revenue 22,619,536 25,139,419
Services Segment | Installation Services [Member]    
Disaggregation of Revenue [Line Items]    
Revenue 16,074,870 14,523,054
Services Segment | Energy Production    
Disaggregation of Revenue [Line Items]    
Revenue 2,100,670 1,756,419
Operating Segments    
Disaggregation of Revenue [Line Items]    
Revenue 22,619,536 25,139,419
Operating Segments | Products Segment    
Disaggregation of Revenue [Line Items]    
Revenue 4,443,996 8,859,946
Operating Segments | Energy Production    
Disaggregation of Revenue [Line Items]    
Revenue $ 2,100,670 $ 1,756,419