The world’s first carbon neu­trally pro­duced whiskeys are dis­tilled using Oilon heat pumps 

The unique zero-​emission dis­til­la­tion process of the Irish Ahascragh Dis­tillery has been imple­mented with a com­pre­hen­sive system design applied from the process indus­try: at the core are Oilon’s high tem­per­a­ture heat pumps, with which all the waste heat is put to use.

In the village of Ahascragh, about a two-​hour drive from Dublin, there lies an over 200-​year-old brick mill where grain was ground into flour from the early 1800s until the 1950s. Now, this mag­nif­i­cent his­toric build­ing has been given a new life as the world’s first carbon neutral whiskey dis­tillery, which opened its doors in the summer of 2023.

‘Dis­till­ing whiskey is very energy inten­sive: Each bottle of tra­di­tion­ally dis­tilled whiskey pro­duces 3-4 kilo­grams of carbon dioxide emis­sions. Now, we are proud to be able to offer con­sumers a whiskey alter­na­tive whose pro­duc­tion has not harmed the envi­ron­ment,’ Gareth McAl­lis­ter, the owner of Ahascragh Dis­tillery, says.

Unlike other dis­til­leries in Ireland, heat is pro­vided to the dis­tillery through heat pumps which means that there will be no flue related emis­sions, or impacts on the local envi­ron­ment. 

Almost 120-degree water for the process with the help of pumps   

Ireland pro­duces plenty of green elec­tric­ity: In 2022, 34 percent of the country’s elec­tric­ity pro­duc­tion (about 13.2 TWh)  was wind power. Instead, thermal energy in the island state is still largely pro­duced with fossil fuels. Even thermal energy used in whiskey dis­til­la­tion has tra­di­tion­ally been pro­duced with natural gas.

‘In Ahascragh, the heat needed for the process is pro­duced by high tem­per­a­ture heat pumps instead of natural gas. The pumps are powered by wind-​generated elec­tric­ity. In this way, we have been able to get rid of fossil fuels and the process has become zero-​emission,’ McAl­lis­ter explains.

Oilon has deliv­ered two P450 series heat pumps and one smaller P150 heat pump to the dis­tillery. P450 series pumps are capable of pro­duc­ing tem­per­a­tures of up to 120 degrees, in Ahascragh the design tem­per­a­ture is 115 degrees. The pumps also use the latest refrig­er­ant tech­nol­ogy: they have a very low GWP value (Global Warming Poten­tial).

Oilon’s expe­ri­ence in process indus­try heat pump solu­tions was uti­lized in the project. The Irish company Asta­tine which spe­cial­izes in carbon-​neutral turnkey solu­tions was respon­si­ble for the overall design of the system.

Waste heat recov­ery and cir­cu­la­tion, COP up 

Two par­al­lel processes work in the dis­tillery: the actual dis­til­la­tion process where alcohol is alter­nately steamed and con­densed in a closed circuit, and the auto­matic clean­ing process of the equip­ment, which requires a sig­nif­i­cant amount of warm water.

‘The total COP has been raised to an excep­tion­ally high level by apply­ing the oper­at­ing methods of the process indus­try: heat pump tech­nol­ogy is com­bined with process know-​how, i.e., all gen­er­ated waste heat is recov­ered with the pumps and uti­lized at another point in the process,’ Asta­tine’s manager Tom Marren says.

The heat pump design, heat recov­ery and thermal storage means that the energy inputs to the dis­tillery are a third than that of tra­di­tional tech­nol­ogy. 

At the high tem­per­a­tures of the P450 pumps, the dis­til­la­tion process itself is running. In this process the alcohol alter­nately vapor­izes and con­denses in a closed circuit. The pumps are equipped with sep­a­rate heat exchang­ers which also produce lower tem­per­a­ture water for the washing process. The smaller P150 pump pro­duces domes­tic hot water which can be used for addi­tional cooling of the dis­til­la­tion process if nec­es­sary. ‘Com­pre­hen­sive system plan­ning and com­bi­na­tion of processes was crucial in terms of COP and, of course, reduc­ing emis­sions. The total COP of the process is an astound­ing 6.5. In other words, for every kWh of elec­tric­ity used by the heat pump, it gen­er­ates 6.5 kWh of energy for use in the process. This level of energy effi­ciency is excep­tional and it can only be reached by util­is­ing the energy flows in the process opti­mally,” says Sales and Mar­ket­ing Direc­tor Sami Pekkola from Oilon. 

Design of the overall system